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May.04.2021

Drospirenone

Indications/Dosage

Labeled

  • contraception

Off-Label

    † Off-label indication

    For routine contraception

    Oral dosage

    Adult and Adolescent females

    1 tablet (4 mg drospirenone) PO once daily for 24 days, followed by 4 days of non-hormonal, inactive tablets PO once daily in the order directed on the pack. Cycle repeats every 28 days. Patients should begin taking this product on day 1 of the menstrual cycle (first day of menstruation). When switching from another contraceptive, patients should start taking this oral contraceptive on the same day that a new pack of the previous oral contraceptive would have been started, or on the day when the next transdermal patch application, vaginal ring insertion, or injection would have been scheduled. Patients switching from an IUD or implant to this oral contraceptive should start on the day of removal.[64244]

    Therapeutic Drug Monitoring

    Maximum Dosage Limits

    • Adults

      4 mg/day PO.

    • Geriatric

      Safety and efficacy have not been established.

    • Adolescents

      4 mg/day PO.

    • Children

      Not indicated in prepubescent females.

    • Infants

      Not indicated.

    Patients with Hepatic Impairment Dosing

    Use is contraindicated.[64244]

    Patients with Renal Impairment Dosing

    CrCl less than 80 mL/minute: Use is contraindicated.[64244]

    † Off-label indication
    Revision Date: 05/04/2021, 12:13:27 PM

    References

    64244 - SLYND (drospirenone) tablets package insert. Florham Park, NJ:Exeltis USA Inc..; 2019 May.

    How Supplied

    Drospirenone Oral tablet, Inert Oral tablet

    Slynd 28-Day 4mg Tablet (00642-7470) (Exeltis USA, Inc. formerly Everett Laboratories Inc) null

    Description/Classification

    Description

    Drospirenone is a fourth generation progestin and an analog of spironolactone with antimineralocorticoid and antiandrogenic properties. Drospirenone-only contraceptive regimens prevent pregnancy in females of reproductive potential. In women desiring oral contraception, drospirenone also improves acne in some women due to its antiandrogenic effects. Hormonal progestin-only contraceptives can be used in female patients from menarche to over the age of 40 years up until the time of menopause with proper selection of products. The choice of a routine hormonal contraceptive for any given patient is based on the individual's contraceptive needs, underlying medical conditions or risk factors for adverse effects, and individual preferences for use. The Centers for Disease Control's U.S. Medical Eligibility Criteria describe considerations for risk vs. benefits, including medical conditions or attributes that contraindicate use; these criteria can help prescribing practitioners in product selection for individual patients.[48201] Drospirenone may increase potassium levels in some patients; do not use drospirenone products in patients with significant risks for hyperkalemia, such as those with kidney, liver, or adrenal insufficiency. Patients taking drugs that could increase serum potassium should consult their health care professional before taking drospirenone-containing oral contraceptive products. A drospirenone-only oral contraceptive was FDA-approved in May 2019.

    Classifications

    • Genito-urinary System and Sex Hormones
      • Sex Hormones and Modulators of the Genital System
        • Hormonal Contraceptives
          • Progestogen Only Contraceptives
    Revision Date: 06/05/2019, 11:40:25 AM

    References

    48201 - US Department of Health and Human Services/Centers for Disease Control and Prevention. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. MMWR Recomm Rep. 2016;65:1-103.

    Administration Information

    General Administration Information

    For storage information, see the specific product information within the How Supplied section.

    Hazardous Drugs Classification

    • NIOSH 2016 List: Group 2 [63664]
    • NIOSH (Draft) 2020 List: Table 2
    • Observe and exercise appropriate precautions for handling, preparation, administration, and disposal of hazardous drugs.
    • Use gloves to handle. Cutting, crushing, or otherwise manipulating tablets/capsules will increase exposure and require additional protective equipment. Eye/face and respiratory protection may be needed during preparation and administration.[63664][67506][67507]

    Route-Specific Administration

    Oral Administration

    Oral Solid Formulations

    • To minimize nausea, administer with or after the evening meal or at bedtime. Take at the same time each day to ensure maximum contraceptive efficacy.
    • The blister card contains 24 active hormone tablets and 4 inert tablets. The inert tablets are included so that the daily dosage cycle can be continuous. This reduces the chance of missed doses. The extra tablets are taken at the end of the cycle.[64244]


    Administration instructions for patients:

    • Instruct patient on risks and warnings associated with hormonal contraceptives.
    • Missing pills can cause spotting or light bleeding.
    • Patients should be instructed to review the patient information leaflet that accompanies the prescription each time it is filled.d


    Instructions for missed doses:

    • If 1 white active tablet is missed, the patient should take it as soon as she remembers and then take the next pill at the regular time as usual. The patient should continue taking 1 tablet a day until the pack is finished.
    • If 2 or more white active tablets are missed, the patient should take the last missed tablet as soon as she remembers. The patient should continue 1 tablet a day until the pack is finished (1 or more missed tablet (s) will remain in the blister pack). Additional non-hormonal contraception (such as condoms or spermicide) should be used as back-up if the patient has sex within 7 days after missing tablets.
    • If 1 or more green inert tablets are missed, the patient should skip the missed pill days and continue taking 1 tablet a day until the pack is finished.[64244]

     

    Advice in Case of Gastrointestinal Disturbances:
    If vomiting or diarrhea occurs within 3 to 4 hours after tablet taking, the new tablet (scheduled for the next day) should be taken as soon as possible. The new tablet should be taken within 12 hours of the usual time of tablet-taking if possible. If more than 2 tablets are missed, the advice concerning 2 missed tablets, including using backup non-hormonal contraception, is applicable.[64244]

    Clinical Pharmaceutics Information

    From Trissel's 2‚Ñ¢ Clinical Pharmaceutics Database
      Revision Date: 04/28/2022, 12:05:58 PM

      References

      63664 - CDC National Institute for Occupational Safety and Health (NIOSH). NIOSH List of Antineoplastic and Other Hazardous Drugs in Healthcare Settings 2016. DHHS (NIOSH) Publication Number 2016-161, September 2016. Available on the World Wide Web at https://www.cdc.gov/niosh/docs/2016-161/pdfs/2016-161.pdf?id=10.26616/NIOSHPUB201616164244 - SLYND (drospirenone) tablets package insert. Florham Park, NJ:Exeltis USA Inc..; 2019 May.67506 - American Society of Health-System Pharmacists. ASHP guidelines on handling hazardous drugs. Am J Health-Syst Pharm. 2018; 75:1996-2031.67507 - NIOSH [2016]. NIOSH Alert: Preventing Occupational Exposures to Antineoplastics and Other Hazardous Drugs in Health Care Settings. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2016-161.

      Adverse Reactions

      Mild

      • acne vulgaris
      • amenorrhea
      • breakthrough bleeding
      • breast discharge
      • breast enlargement
      • dysmenorrhea
      • headache
      • libido decrease
      • mastalgia
      • menorrhagia
      • menstrual irregularity
      • nausea
      • oligomenorrhea
      • pelvic pain
      • weight gain

      Moderate

      • galactorrhea
      • lactation suppression

      Severe

      • hyperkalemia

      Breast tenderness or mastalgia (1.2%), breast pain (2.2%), breast enlargement, and breast discharge or secretion have been reported in patients receiving oral contraceptives such as drospirenone and are believed to be drug-related.[64244] Galactorrhea and lactation suppression may also occur.

      Breakthrough bleeding (spotting) (1.7%) and metrorrhagia (2.8%) are sometimes encountered, especially during the first 3 months of oral contraceptive use such as drospirenone. Change in menstrual flow (menstrual irregularity) (1.2%) and amenorrhea have also been reported and are believed to be drug-related. Other adverse effects may include dysmenorrhea (1.9%), menorrhagia, oligomenorrhea, and pelvic pain. Based on subject diaries from 4 clinical trials of drospirenone, 64.4% of females experienced unscheduled bleeding at Cycle 1. This percentage decreased to 40.3% by cycle 13. A total of 91 out of 2593 subjects (0.4%) discontinued drospirenone due to menstrual bleeding disorders including metrorrhagia, menstrual irregular, vaginal hemorrhage, menorrhagia, uterine hemorrhage, and amenorrhea. In the event of breakthrough vaginal bleeding, consider nonhormonal causes and take adequate diagnostic measures to rule out malignancy or pregnancy. If pathology has been excluded, time or a change to another formulation may solve the problem. In the event of amenorrhea, rule out pregnancy. Some women may encounter post-pill amenorrhea or oligomenorrhea, especially when such a condition was pre-existent.[64244]



      Weight gain was reported in 1.9% of patients receiving drospirenone.[64244]

      Nausea was reported in 1.8% of patients receiving drospirenone.[64244]

      Libido decrease was reported in 1.3% of patients receiving drospirenone.[64244]

      Headache was reported in 2.7% of patients receiving drospirenone.[64244]

      Acne vulgaris was reported in 3.8% of patients receiving drospirenone.[64244]

      The antimineralocorticoid actions of 3 mg of drospirenone are comparable to 25 mg of spironolactone and may cause hyperkalemia in predisposed patients. Most females with hyperkalemia in the clinical development studies of drospirenone had mild potassium elevations and/or isolated increases that returned to normal while still on study medication. No concurrent adverse reactions were attributed to hyperkalemia. In the pivotal trial, 2 females (0.2%) with persistent potassium elevations discontinued drospirenone. It is essential to avoid drospirenone in patients with adrenal insufficiency, hepatic disease, or renal disease, who are at higher risk for hyperkalemia from drospirenone.[64244]

      Revision Date: 05/04/2021, 11:59:21 AM

      References

      64244 - SLYND (drospirenone) tablets package insert. Florham Park, NJ:Exeltis USA Inc..; 2019 May.

      Contraindications/Precautions

      Absolute contraindications are italicized.

      • adrenal insufficiency
      • breast cancer
      • cervical cancer
      • hepatic disease
      • hepatocellular cancer
      • jaundice
      • pregnancy
      • renal disease
      • renal failure
      • renal impairment
      • uterine cancer
      • vaginal bleeding
      • acquired immunodeficiency syndrome (AIDS)
      • breast-feeding
      • children
      • depression
      • diabetes mellitus
      • ectopic pregnancy
      • headache
      • human immunodeficiency virus (HIV) infection
      • hyperkalemia
      • menstrual irregularity
      • migraine
      • myocardial infarction
      • osteopenia
      • sexually transmitted disease
      • stroke
      • thromboembolic disease
      • thromboembolism
      • tobacco smoking

      Drospirenone does not protect against human immunodeficiency virus (HIV) infection or other sexually transmitted disease. Patients with known HIV infection or acquired immunodeficiency syndrome (AIDS) should be aware that the use of this oral hormonal contraceptive (OC) will not prevent the transmission of HIV or other sexually-transmitted diseases to their partner(s).[64244]

      Drospirenone has antimineralocorticoid activity and may increase serum potassium. Because of the antimineralocorticoid activity, drospirenone may predispose certain patients to hyperkalemia or impaired adrenal function; thus drospirenone is contraindicated in patients with renal impairment (i.e., CrCl less than 80 mL/minute), renal disease, renal failure, or adrenal insufficiency. Females receiving daily, long-term treatment for chronic conditions or diseases with medications that may increase serum potassium concentration should have their serum potassium concentration checked prior to starting treatment and during the first treatment cycle. Such medications include potassium-sparing medications or strong CYP3A4 inhibitors. Monitor females taking drospirenone who later develop medical conditions and/or begin medication that put them at an increased risk for hyperkalemia.[64244]

      Drospirenone is contraindicated in patients with hepatic disease, jaundice, or hepatic tumors (benign or hepatocellular cancer). The mean exposure to drospirenone in females with moderate hepatic impairment is approximately 3 times higher than the exposure in females with normal liver function. Increased drospirenone exposure increases risks for hyperkalemia and other side effects. Discontinue drospirenone use if jaundice or acute or chronic disturbances of liver function develop. Do not resume use until markers of liver function return to normal and drospirenone causation has been excluded.[64244]

      Epidemiological studies have not indicated an association between progestin-only preparations and an increased risk of arterial or venous thromboembolism. When prescribing drospirenone, consider the increased risk of thromboembolism inherent in the postpartum period and in females with a known history of thromboembolism, including myocardial infarction or stroke. Discontinue drospirenone if arterial or venous thromboembolic events occur.[64244] Tobacco smoking increases the risk of serious cardiovascular disease, myocardial infarction, and stroke. Women who use oral contraceptives should be strongly advised not to smoke. There are no studies definitely linking progestin-only pill (POP) use to an increased risk of heart attack or stroke.[48201] Despite the caution against use in patients with known thrombotic disease, progestin-only contraceptives are generally the hormonal contraceptives of choice in patients with a potential risk for thrombosis when reliable contraception must be ensured and the risks of hormonal therapy are acceptable; advantages of these methods usually outweigh proven or theoretical risks.[48201] When multiple risk factors exist for thromboembolic disease (e.g., tobacco smoking, women 35 years and older, diabetes, cerebrovascular disease, hypercoagulopathy, valvular or ischemic heart disease, severe hypertension, etc.), the risk of thromboembolic disease may increase; determine individual risk vs. benefit for use of the progestin-only contraceptive. The increase in the risk of thrombosis from newer progestin-only contraceptives (e.g.,drospirenone) is still substantially less than with combined oral contraceptives containing both estrogen and progestin.[48201] Consider discontinuing drospirenone, if feasible, in case of prolonged immobilization due to major surgery or illness, since these situations increase risk for thromboembolism.[64244]

      Drospirenones should be used cautiously in patients with diabetes mellitus. Although the effects appear to be minimal during therapy with progestins, altered glucose tolerance secondary to decreased insulin sensitivity has been reported during hormonal contraceptive therapy.[64244]

      Use drospirenone with caution in a patient with a history of migraine, particularly migraine with aura or if the patient is 35 years of age or older. The onset or exacerbation of migraine or the development of headache with a new pattern that is recurrent, persistent, or severe requires evaluation of the cause.[48201]

      Mood disorders, like depression, may be aggravated in women taking exogenous hormones. Women with a history of depression may need special monitoring. Data on the association of progestin-only contraceptive products with onset of depression or exacerbation of depression are limited. If significant depression occurs, drospirenone should be discontinued.[64244]

      Drospirenone is contraindicated in patients with known or suspected progestin-sensitive cancers, such as breast cancer. Progestin-only oral contraceptives do not appear to cause breast cancer. However patients who have or have had a cancer that may be sensitive to hormones should not use hormonal contraceptives.[64244] [48201]

      Drospirenone is contraindicated in undiagnosed abnormal vaginal bleeding and in patients with known or suspected progestin-sensitive cancers of reproductive organs, such as cervical cancer or uterine cancer. Women who use hormonal contraceptives may have a higher chance of getting cervical cancer. However, the increased risk observed with some hormonal contraceptives may be due to other reasons such as having more sexual partners and exposure to the human papilloma virus (HPV).[64244]

      Patients should be instructed that menstrual irregularity may occur and to notify their prescriber of any persistent changes in bleeding patterns; these may require medical evaluation. Some women may experience unscheduled (breakthrough or intracyclic) bleeding and spotting especially during the first 3 months of use of drospirenone. Bleeding irregularities may resolve over time or by changing to a different contraceptive product. If bleeding persists or occurs after previously regular cycles, evaluate for the cause, including malignancy. If scheduled bleeding does not occur, consider the possibility that the patient may be pregnant, particularly if the patient has not adhered to the prescribed dosing schedule, or if the patient has adhered to the prescribed dosing schedule and misses 2 consecutive menstrual periods.[64244]

      Drospirenone is contraindicated for use during pregnancy, as there is no reason to continue use during pregnancy There appears to be little or no increased risk of birth defects in children born to women who have used oral progestins inadvertently during early pregnancy. Recent studies have found no increased risk of of genital or nongenital birth defects (including cardiac anomalies and limb-reduction defects) among women who have inadvertently continued to take birth control pills after they unknowingly became pregnant. In any patient in whom pregnancy is suspected, pregnancy should be ruled out before continuing oral contraceptive use. Be alert to the possibility of ectopic pregnancy in females who become pregnant or complain of lower abdominal pain while on drospirenone.[64244] Progestin-only oral contraceptive users have a higher absolute rate of ectopic pregnancy than do users of other hormonal contraceptives, but the risk is still lower than women using no method.[48201]

      Negligible amounts of drospirenone are excreted into breast milk during routine oral contraceptive use, resulting in infant plasma levels that are approximately 1.5% of those found in maternal plasma, even with exclusive breast-feeding. At therapeutic doses of drospirenone, no effects on breastfed newborns/infants are anticipated. In general, no adverse effects have been found on milk production or on the health growth, or development of the infant with use of progestin-only oral contraceptives.[64244] Alternate contraceptive agents for consideration include non-hormonal contraceptive methods and also other progestin-only contraceptives, such as medroxyprogesterone contraceptive injection (e.g., Depo-Provera).[48201] When prescribing drospirenone, consider the increased risk of thromboembolism inherent in the postpartum period.[64244]

      The safety and efficacy of drospirenone products have only been established in females of reproductive age. Safety and efficacy of drospirenone is expected to be the same for postpubertal female children under the age of 16 years and for users 16 years and older. Use of drospirenone products in female pediatric patients before menarche is not indicated.[64244]

      Treatment with drospirenone leads to decreased estradiol serum levels in treated females. It is unknown if this may cause a clinically relevant loss of bone mineral density (osteopenia).[64244]

      Revision Date: 06/05/2019, 04:03:32 PM

      References

      48201 - US Department of Health and Human Services/Centers for Disease Control and Prevention. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. MMWR Recomm Rep. 2016;65:1-103.64244 - SLYND (drospirenone) tablets package insert. Florham Park, NJ:Exeltis USA Inc..; 2019 May.

      Mechanism of Action

      The contraceptive effect of drospirenone is achieved primarily by the suppression of ovulation. Progestins also thicken the cervical mucus to inhibit sperm penetration and make the endometrial lining less suitable for implantation. Drospirenone has no androgenic, estrogenic, glucocorticoid, or antiglucocorticoid activity. As an analog of spironolactone, the drug exhibits both antimineralocorticoid and antiandrogenic activity. Thus this progestin inhibits testosterone production by the ovaries and adrenal glands, as well as some peripheral testosterone synthesis. Drospirenone's endocrine activity may improve luteal symptoms such as negative mood, water retention, and increased appetite. However, the antimineralocorticoid actions of drospirenone are comparable to spironolactone and may increase serum potassium levels in some patients. Progestins in general can alter hepatic carbohydrate metabolism, increase insulin resistance, and have either little to slightly favorable effects on serum lipoproteins. Less androgenic progestins, like drospirenone, have only slight effects on carbohydrate metabolism and are less likely to aggravate acne or blood pressure.[64244][60767][51282]

      Revision Date: 06/05/2019, 12:27:37 PM

      References

      51282 - Sitruk-Ware R. Pharmacology of different progestogens: the special case of drospirenone. Climacteric 2005;8:4-12.60767 - Brunton LB, Lazo JS, Parker KL, eds. Goodman & Gilman's The Pharmacological Basis of Therapeutics, 11th ed. New York: McGraw-Hill; 2006.64244 - SLYND (drospirenone) tablets package insert. Florham Park, NJ:Exeltis USA Inc..; 2019 May.

      Pharmacokinetics

      Drospirenone is administered orally, and like other progestins, is widely distributed. Drospirenone is 97% bound to other serum proteins and does not bind to SHBG or CBG. Drospirenone is extensively metabolized to 2 main metabolites, the acid form of drospirenone and the 4,5-dihydrodrospirenone-3-sulfate. These metabolites were shown not to be pharmacologically active. Drospirenone is also subject to oxidative metabolism catalyzed by CYP3A4. Excretion of drospirenone as inactive metabolites occurs via the urine and feces. The terminal elimination half-life is approximately 30 hours. It is the prolonged biologic effects of the hormone that allows for once-daily administration.[64244]



      Affected cytochrome P450 (CYP450) isoenzymes and drug transporters: CYP3A4

      Drospirenone is subject to oxidative metabolism catalyzed by CYP3A4. Drugs or herbal products that induce CYP3A4 may decrease the systemic concentrations of drospirenone and potentially diminish the effectiveness of drospirenone or increase the risk of breakthrough bleeding. Drugs that are potent inhibitors of CYP3A4 may moderately increase drospirenone concentrations.[64244]

      Route-Specific Pharmacokinetics

      Oral Route

      The pharmacokinetics of oral drospirenone is dose-proportional following single doses ranging from 1 to 10 mg. Following a single ingestion of drospirenone, maximum concentrations (Cmax) of drospirenone in plasma of about 27 ng/mL are attained at 2 to 6 hours. During a treatment cycle, maximum steady-state concentrations of drospirenone in serum of about 41 ng/mL are reached after about 10 days of treatment. Plasma drospirenone Cmax and area under the curve (AUC) accumulate by a factor of about 1.5 to 2 following multiple dose administration. Concomitant ingestion of food has no influence on the extent of absorption of drospirenone.[64244]

      Special Populations

      Hepatic Impairment

      Drospirenone is contraindicated in patients with hepatic disease. The mean exposure to drospirenone in females with moderate liver impairment is approximately 3 times higher than the exposure in females with normal liver function. Drospirenone has not been studied in patients with severe hepatic impairment.[64244]

      Renal Impairment

      In a pharmacokinetic study, drospirenone kinetics and its effect on serum potassium were evaluated in the presence of renal impairment. All subjects (n = 28) were on a low potassium diet, and 7 subjects were allowed to continue use of potassium-sparing drugs. At day 14 of treatment, similar drospirenone concentrations were observed between subjects with normal renal function (CrCl more than 80 mL/minute) and those with mild renal impairment (CrCl 50 to 80 mL/minute). Drospirenone concentrations were 37% greater among patients with moderate renal impairment (CrCl 30 to 50 mL/minute) compared to those with normal renal function. No clinically significant effect on serum potassium concentration were observed during the study. Hyperkalemia was not observed; however, serum potassium concentrations increased by up to 0.33 mEq/L in 5 of 7 patients allowed to continue use of potassium-sparing drugs.[64244]

      Revision Date: 06/05/2019, 04:28:15 PM

      References

      64244 - SLYND (drospirenone) tablets package insert. Florham Park, NJ:Exeltis USA Inc..; 2019 May.

      Pregnancy/Breast-feeding

      ectopic pregnancy, pregnancy

      Drospirenone is contraindicated for use during pregnancy, as there is no reason to continue use during pregnancy There appears to be little or no increased risk of birth defects in children born to women who have used oral progestins inadvertently during early pregnancy. Recent studies have found no increased risk of of genital or nongenital birth defects (including cardiac anomalies and limb-reduction defects) among women who have inadvertently continued to take birth control pills after they unknowingly became pregnant. In any patient in whom pregnancy is suspected, pregnancy should be ruled out before continuing oral contraceptive use. Be alert to the possibility of ectopic pregnancy in females who become pregnant or complain of lower abdominal pain while on drospirenone.[64244] Progestin-only oral contraceptive users have a higher absolute rate of ectopic pregnancy than do users of other hormonal contraceptives, but the risk is still lower than women using no method.[48201]

      breast-feeding

      Negligible amounts of drospirenone are excreted into breast milk during routine oral contraceptive use, resulting in infant plasma levels that are approximately 1.5% of those found in maternal plasma, even with exclusive breast-feeding. At therapeutic doses of drospirenone, no effects on breastfed newborns/infants are anticipated. In general, no adverse effects have been found on milk production or on the health growth, or development of the infant with use of progestin-only oral contraceptives.[64244] Alternate contraceptive agents for consideration include non-hormonal contraceptive methods and also other progestin-only contraceptives, such as medroxyprogesterone contraceptive injection (e.g., Depo-Provera).[48201] When prescribing drospirenone, consider the increased risk of thromboembolism inherent in the postpartum period.[64244]

      Revision Date: 06/04/2019, 01:07:40 PM

      References

      48201 - US Department of Health and Human Services/Centers for Disease Control and Prevention. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. MMWR Recomm Rep. 2016;65:1-103.64244 - SLYND (drospirenone) tablets package insert. Florham Park, NJ:Exeltis USA Inc..; 2019 May.

      Interactions

      Level 1 (Severe)

      • Atazanavir
      • Atazanavir; Cobicistat

      Level 2 (Major)

      • Apalutamide
      • Aprepitant, Fosaprepitant
      • Armodafinil
      • Belzutifan
      • Bexarotene
      • Bosentan
      • Calaspargase pegol
      • Carbamazepine
      • Cenobamate
      • Charcoal
      • Clobazam
      • Cobicistat
      • Dabrafenib
      • Darunavir
      • Darunavir; Cobicistat
      • Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide
      • Efavirenz
      • Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate
      • Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate
      • Elagolix
      • Elagolix; Estradiol; Norethindrone acetate
      • Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide
      • Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate
      • Encorafenib
      • Enzalutamide
      • Eslicarbazepine
      • Etravirine
      • Felbamate
      • Fosamprenavir
      • Griseofulvin
      • Hydantoins
      • Indinavir
      • Isoniazid, INH; Pyrazinamide, PZA; Rifampin
      • Isoniazid, INH; Rifampin
      • Ivosidenib
      • Lesinurad
      • Lesinurad; Allopurinol
      • Lomitapide
      • Lorlatinib
      • Lumacaftor; Ivacaftor
      • Mavacamten
      • Mifepristone
      • Mitotane
      • Mobocertinib
      • Modafinil
      • Nelfinavir
      • Oxcarbazepine
      • Pegaspargase
      • Pexidartinib
      • Pitolisant
      • Pretomanid
      • Rifampin
      • Rifapentine
      • Rufinamide
      • Sotorasib
      • St. John's Wort, Hypericum perforatum
      • Sugammadex
      • Tazemetostat
      • Tipranavir
      • Tirzepatide
      • Tizanidine
      • Ulipristal

      Level 3 (Moderate)

      • Adagrasib
      • Aliskiren
      • Aliskiren; Amlodipine
      • Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ
      • Aliskiren; Hydrochlorothiazide, HCTZ
      • Aliskiren; Valsartan
      • Amikacin
      • Amiloride
      • Amiloride; Hydrochlorothiazide, HCTZ
      • Aminoglycosides
      • Amobarbital
      • Amoxicillin
      • Amoxicillin; Clarithromycin; Omeprazole
      • Amoxicillin; Clavulanic Acid
      • Ampicillin
      • Ampicillin; Sulbactam
      • Angiotensin II receptor antagonists
      • Angiotensin-converting enzyme inhibitors
      • Aspirin, ASA; Butalbital; Caffeine
      • Aspirin, ASA; Butalbital; Caffeine; Codeine
      • Azithromycin
      • Aztreonam
      • Bacitracin
      • Barbiturates
      • Bismuth Subcitrate Potassium; Metronidazole; Tetracycline
      • Bismuth Subsalicylate; Metronidazole; Tetracycline
      • Butabarbital
      • Butalbital; Acetaminophen
      • Butalbital; Acetaminophen; Caffeine
      • Butalbital; Acetaminophen; Caffeine; Codeine
      • Carbapenems
      • Cefaclor
      • Cefadroxil
      • Cefazolin
      • Cefdinir
      • Cefditoren
      • Cefepime
      • Cefiderocol
      • Cefixime
      • Cefotaxime
      • Cefotetan
      • Cefoxitin
      • Cefpodoxime
      • Cefprozil
      • Ceftaroline
      • Ceftazidime
      • Ceftazidime; Avibactam
      • Ceftibuten
      • Ceftizoxime
      • Ceftolozane; Tazobactam
      • Ceftriaxone
      • Cefuroxime
      • Cephalexin
      • Chloramphenicol
      • Ciprofloxacin
      • Clarithromycin
      • Clindamycin
      • Colistimethate, Colistin, Polymyxin E
      • Colistin
      • Dalbavancin
      • Daptomycin
      • Deferasirox
      • Delafloxacin
      • Demeclocycline
      • Dicloxacillin
      • Doripenem
      • Doxycycline
      • Eplerenone
      • Eravacycline
      • Ertapenem
      • Erythromycin
      • Exenatide
      • Fidaxomicin
      • Finerenone
      • Flibanserin
      • Gemifloxacin
      • Gentamicin
      • Glycylcyclines
      • Idelalisib
      • Imipenem; Cilastatin
      • Imipenem; Cilastatin; Relebactam
      • Insulin Glargine; Lixisenatide
      • Itraconazole
      • Kanamycin
      • Ketoconazole
      • Lamotrigine
      • Lansoprazole; Amoxicillin; Clarithromycin
      • Lefamulin
      • Leflunomide
      • Levofloxacin
      • Levoketoconazole
      • Lincomycin
      • Lincosamides
      • Linezolid
      • Lixisenatide
      • Lonafarnib
      • Mafenide
      • Meropenem
      • Meropenem; Vaborbactam
      • Methohexital
      • Metronidazole
      • Miltefosine
      • Minocycline
      • Mivacurium
      • Morphine
      • Morphine; Naltrexone
      • Moxifloxacin
      • Nafcillin
      • Neomycin
      • Nevirapine
      • Nitrofurantoin
      • Ofloxacin
      • Omadacycline
      • Omeprazole; Amoxicillin; Rifabutin
      • Oritavancin
      • Oxacillin
      • Paromomycin
      • Penicillin G
      • Penicillin G Benzathine
      • Penicillin G Benzathine; Penicillin G Procaine
      • Penicillin G Procaine
      • Penicillin V
      • Pentobarbital
      • Phenobarbital
      • Phenobarbital; Hyoscyamine; Atropine; Scopolamine
      • Phentermine; Topiramate
      • Piperacillin
      • Piperacillin; Tazobactam
      • Plazomicin
      • Polymyxin B
      • Posaconazole
      • Potassium
      • Potassium-sparing diuretics
      • Prasterone, Dehydroepiandrosterone, DHEA (Dietary Supplements)
      • Prasterone, Dehydroepiandrosterone, DHEA (FDA-approved)
      • Primidone
      • Riluzole
      • Roflumilast
      • Sarilumab
      • Secobarbital
      • Siltuximab
      • Spironolactone
      • Spironolactone; Hydrochlorothiazide, HCTZ
      • Streptogramins
      • Streptomycin
      • Succinylcholine
      • Sulfadiazine
      • Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole
      • Sulfasalazine
      • Sulfonamides
      • Tedizolid
      • Telavancin
      • Teriflunomide
      • Tetracycline
      • Thalidomide
      • Tigecycline
      • Tinidazole
      • Tobramycin
      • Tocilizumab
      • Topiramate
      • Triamterene
      • Triamterene; Hydrochlorothiazide, HCTZ
      • Trimethoprim
      • Tucatinib
      • Vancomycin
      • Vonoprazan; Amoxicillin
      • Vonoprazan; Amoxicillin; Clarithromycin
      • Voriconazole

      Level 4 (Minor)

      • Acetohexamide
      • Alogliptin
      • Alogliptin; Metformin
      • Alogliptin; Pioglitazone
      • Alpha-glucosidase Inhibitors
      • Bromocriptine
      • Canagliflozin
      • Canagliflozin; Metformin
      • Chenodiol
      • Chlorpropamide
      • Dapagliflozin
      • Dapagliflozin; Metformin
      • Dapagliflozin; Saxagliptin
      • Delavirdine
      • Empagliflozin
      • Empagliflozin; Linagliptin
      • Empagliflozin; Linagliptin; Metformin
      • Empagliflozin; Metformin
      • Ertugliflozin
      • Ertugliflozin; Metformin
      • Ertugliflozin; Sitagliptin
      • Fluvoxamine
      • Glimepiride
      • Glimepiride; Rosiglitazone
      • Glipizide
      • Glipizide; Metformin
      • Glyburide
      • Glyburide; Metformin
      • grapefruit juice
      • Heparin
      • Insulins
      • Linagliptin
      • Linagliptin; Metformin
      • Meglitinides
      • Metformin
      • Metformin; Repaglinide
      • Metformin; Rosiglitazone
      • Metformin; Saxagliptin
      • Metformin; Sitagliptin
      • Nefazodone
      • Nonsteroidal antiinflammatory drugs
      • Pioglitazone
      • Pioglitazone; Glimepiride
      • Pioglitazone; Metformin
      • Pramlintide
      • Rosiglitazone
      • Saquinavir
      • Saxagliptin
      • Simvastatin; Sitagliptin
      • Sitagliptin
      • Sulfonylureas
      • Thiazolidinediones
      • Tolazamide
      • Tolbutamide
      Acetohexamide: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Adagrasib: (Moderate) Use caution if coadministration of adagrasib with progestins is necessary, as the systemic exposure of progestins may be increased resulting in an increase in treatment-related adverse reactions. Progestins are metabolized primarily by hydroxylation via a CYP3A; adagrasib is a strong CYP3A inhibitor. [63694] [68325] Aliskiren: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium, therefore concurrent use of aliskiren may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if aliskiren is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Aliskiren; Amlodipine: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium, therefore concurrent use of aliskiren may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if aliskiren is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium, therefore concurrent use of aliskiren may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if aliskiren is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Aliskiren; Hydrochlorothiazide, HCTZ: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium, therefore concurrent use of aliskiren may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if aliskiren is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Aliskiren; Valsartan: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium, therefore concurrent use of aliskiren may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if aliskiren is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Alogliptin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Alogliptin; Metformin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] Alogliptin; Pioglitazone: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Alpha-glucosidase Inhibitors: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [4995] Amikacin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Amiloride: (Moderate) Monitor serum potassium concentration during concomitant drospirenone and potassium-sparing diuretic use due to increased risk for hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia. [31698] [40219] [41929] [42068] [42851] Amiloride; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum potassium concentration during concomitant drospirenone and potassium-sparing diuretic use due to increased risk for hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia. [31698] [40219] [41929] [42068] [42851] Aminoglycosides: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Amobarbital: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Amoxicillin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Amoxicillin; Clarithromycin; Omeprazole: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. Strong CYP3A4 inhibitors include clarithromycin. [28238] [28482] [28509] [31698] [34329] Amoxicillin; Clavulanic Acid: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ampicillin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ampicillin; Sulbactam: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Angiotensin II receptor antagonists: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of angiotensin II receptor antagonists (ARBs) may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if ARBs are used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Angiotensin-converting enzyme inhibitors: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium. The concurrent use of ACE inhibitors may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if an Angiotensin-Converting Enzyme inhibitor (ACE inhibitor) is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Apalutamide: (Major) Progestins are susceptible to drug interactions with hepatic enzyme inducing drugs such as apalutamide. Concurrent administration of apalutamide with progestins, oral contraceptives, or non-oral combination contraceptives may reduce hormonal concentrations. Progestins are CYP3A4 substrates and apalutamide is a strong CYP3A4 inducer. If the hormone is used for contraception, an alternate or additional form of contraception should be considered. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of apalutamide. Monitor hormonal replacement therapy for loss of efficacy while on apalutamide, with dose adjustments as needed. Women taking hormonal replacement and apalutamide should report breakthrough bleeding to their prescribers. This interaction does not apply to vaginal preparations of progesterone (e.g., Crinone, Endometrin). [62874] [63694] Aprepitant, Fosaprepitant: (Major) If aprepitant, fosaprepitant is coadministered with hormonal contraceptives, including hormonal contraceptive devices (skin patches, implants, and hormonal IUDs), use an alternative or back-up non-hormonal method of contraception (e.g., condoms, spermicides) during treatment and for at least 1 month following the last dose of aprepitant, fosaprepitant. The efficacy of progestins may be reduced when coadministered with aprepitant, fosaprepitant and for 28 days after the last dose. The exact mechanism for this interaction has not been described. Progestins are CYP3A4 substrates and aprepitant, fosaprepitant is a CYP3A4 inducer; however, aprepitant, fosaprepitant is also a dose-dependent weak-to-moderate CYP3A4 inhibitor. When administered as an oral 3-day regimen (125mg/80mg/80mg) in combination with ondansetron and dexamethasone, aprepitant decreased trough concentrations of ethinyl estradiol and norethindrone by up to 64% for 3 weeks post-treatment. When ethinyl estradiol and norgestimate were administered on days 1 to 21 and aprepitant (40mg) give as a single dose on day 8, the AUC of ethinyl estradiol decreased by 4% on day 8 and by 29% on day 12; the AUC of norelgestromin increased by 18% on day 8, and decreased by 10% on day 12. Trough concentrations of both ethinyl estradiol and norelgestromin were generally lower after coadministration of aprepitant (40mg) on day 8 compared to administration without aprepitant. Specific studies have not been done with other hormonal contraceptives (e.g., progestins, non-oral combination contraceptives), an alternative or additional non-hormonal method of birth control during treatment and for 28 days after treatment is prudent to avoid potential for contraceptive failure. The clinical significance of this is not known since aprepitant, fosaprepitant is only used intermittently. [30676] [40617] [47343] [57085] Armodafinil: (Major) Armodafinil may cause failure of oral contraceptives or hormonal contraceptive-containing implants or devices due to induction of CYP3A4 isoenzyme metabolism of estrogens and/or the progestins in these products. Female patients of child-bearing potential should be advised to discuss contraceptive options with their health care provider to prevent unintended pregnancies. An alternative method or an additional method of contraception should be utilized during armodafinil therapy and continued for one month after armodafinil discontinuation. [33467] Aspirin, ASA; Butalbital; Caffeine: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Aspirin, ASA; Butalbital; Caffeine; Codeine: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Atazanavir: (Contraindicated) Coadministration of drospirenone and atazanavir boosted with cobicistat is contraindicated. Taking these drugs concurrently increases drospirenone systemic concentrations, which may result in hyperkalemia. [28142] [58000] Atazanavir; Cobicistat: (Contraindicated) Coadministration of drospirenone and atazanavir boosted with cobicistat is contraindicated. Taking these drugs concurrently increases drospirenone systemic concentrations, which may result in hyperkalemia. [28142] [58000] (Major) Drospirenone may be administered concurrently with cobicistat; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with cobicistat may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [51664] [58000] Azithromycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Aztreonam: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Bacitracin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Barbiturates: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Belzutifan: (Major) Women taking both progestins and belzutifan should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed belzutifan. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of belzutifan. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and belzutifan is a weak CYP3A4 inducer. [33322] [57648] [66875] Bexarotene: (Major) Bexarotene capsules may theoretically increase the rate of metabolism and reduce plasma concentrations of substrates metabolized by CYP3A4, including oral contraceptives. It is recommended that two reliable forms of contraception be used simultaneously during oral bexarotene therapy. It is strongly recommended that one of the forms of contraception be non-hormonal. Additionally, because of possible CYP3A4 induction, bexarotene may also decrease the efficacy of hormones used for hormone replacement therapy. [4791] [4792] Bismuth Subcitrate Potassium; Metronidazole; Tetracycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Bismuth Subsalicylate; Metronidazole; Tetracycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Bosentan: (Major) Hormonal contraceptives should not be used as the sole method to prevent pregnancy in patients receiving bosentan. There is a possibility of contraceptive failure when bosentan is coadministered with products containing estrogens and/or progestins. Bosentan is teratogenic. To prevent pregnancy, females of reproductive potential must use 2 acceptable contraception methods during treatment and for 1 month after discontinuation of bosentan therapy. The patient may choose 1 highly effective contraceptive form, including an intrauterine device (IUD) or tubal sterilization, a combination of a hormonal contraceptive with a barrier method, or 2 barrier methods. If a male partner's vasectomy is chosen as a method of contraception, a hormonal or barrier method must still be used by the female patient. Hormonal contraceptives, including oral contraceptives or non-oral combination contraceptives (injectable, transdermal, and implantable contraceptives) may not be reliably effective in the presence of bosentan, since many contraceptive drugs are metabolized by CYP3A4 isoenzymes and bosentan is a significant inducer of CYP3A enzymes. Decreases in hormonal exposure have been documented in drug interaction studies of bosentan with hormonal contraception. Additionally, estrogens and progestins used for hormone replacement therapy (HRT) may also be less effective; patients should be monitored for changes in efficacy such as breakthrough bleeding or an increase in hot flashes. Dosage adjustments may be necessary. [28496] Bromocriptine: (Minor) Bromocriptine is used to restore ovulation and ovarian function in amenorrheic women. Progestins can cause amenorrhea and, therefore, counteract the desired effects of bromocriptine. Concurrent use is not recommended; an alternate form of contraception is recommended during bromocriptine therapy. [5066] Butabarbital: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Butalbital; Acetaminophen: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Butalbital; Acetaminophen; Caffeine: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Butalbital; Acetaminophen; Caffeine; Codeine: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Calaspargase pegol: (Major) The concomitant use of calaspargase pegol and oral contraceptives may reduce the efficacy of oral contraceptives. Women of reproductive potential should use a non-hormonal method of birth control during therapy and for at least 3 months after the last calaspargase pegol dose due to the risk of fetal harm. [63842] Canagliflozin: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Canagliflozin; Metformin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Carbamazepine: (Major) Advise patients taking progestin hormones for contraception to consider an alternate or additional form of contraception, such as nonhormonal and/or barrier methods, during and for at least 1 month following discontinuation of carbamazepine. Higher-dose hormonal regimens may also be considered. Patients taking these hormones for other indications may need to be monitored for reduced clinical effect while on carbamazepine, with dose adjustments made based on clinical efficacy. Progestins are CYP3A substrates and carbamazepine is a strong CYP3A inducer. Concurrent administration may increase progestin elimination. This interaction does not apply to vaginal preparations of progesterone (e.g., Crinone, Endometrin). [28024] [30675] [33322] [41237] [42126] [48201] [57036] [57588] [57648] [63694] Carbapenems: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefaclor: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefadroxil: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefazolin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefdinir: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefditoren: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefepime: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefiderocol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefixime: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefotaxime: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefotetan: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefoxitin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefpodoxime: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefprozil: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ceftaroline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ceftazidime: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ceftazidime; Avibactam: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ceftibuten: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ceftizoxime: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ceftolozane; Tazobactam: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ceftriaxone: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cefuroxime: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Cenobamate: (Major) Women taking both progestins and cenobamate should report breakthrough bleeding to their prescribers. If used for contraception, an alternate or additional form of contraception should be considered in patients prescribed cenobamate. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of cenobamate. Patients taking these hormones for other indications may need to be monitored for reduced clinical effect while on cenobamate, with dose adjustments made based on clinical efficacy. Progestins are CYP3A4 substrates and cenobamate is a moderate CYP3A4 inducer. Concurrent administration may increase progestin elimination. [33322] [57648] [64768] Cephalexin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Charcoal: (Major) Note that charcoal exerts a nonspecific effect, and many medications can be adsorbed by activated charcoal; repeat doses may decrease the enterohepatic recycling of some drugs. Activated charcoal dietary supplements may have the potential to reduce the effectiveness of oral contraceptives. Data clearly demonstrating this interaction are not available. Ovulatory potential was studied during the use of two monophasic oral contraceptive pill preparations, after repeated mid-cycle administration of activated charcoal to treat diarrhea in women. None of eleven women ovulated. Repeated charcoal treatment, when administered 3 hours after but at least 12 hours before pill intake, did not alter oral contraceptive efficacy. [6833] [6834] Chenodiol: (Minor) Estrogens and combination hormonal oral contraceptives increase hepatic cholesterol secretion, and encourage cholesterol gallstone formation and hence may theoretically counteract the effectiveness of chenodiol. [37102] Chloramphenicol: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. Strong CYP3A4 inhibitors include chloramphenicol. [28482] [28509] [29624] [31698] Chlorpropamide: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Ciprofloxacin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Clarithromycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. Strong CYP3A4 inhibitors include clarithromycin. [28238] [28482] [28509] [31698] [34329] Clindamycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Clobazam: (Major) Clobazam induces CYP3A4, which may reduce the concentrations of estrogen and progestin hormones. Hormonal contraceptives may not be reliable when coadministered with clobazam. Females taking hormonal-based birth control should use additional non-hormonal methods and not rely solely on hormonal contraceptive methods when taking clobazam. The additional contraceptive agent may need to be continued for 1 month after discontinuation of the interacting medication. Hormonal contraceptives include combination oral contraceptives, non-oral combination contraceptives, and contraceptives containing only progestins and includes oral, injectable, transdermal, vaginal inserts, and implantable forms of hormonal birth control. Clobazam may also reduce the effectiveness of other estrogens or progestins. Patients taking these hormones for other indications may need to be monitored for reduced clinical effect while on clobazam, with adjustments made based on clinical efficacy. [46370] Cobicistat: (Major) Drospirenone may be administered concurrently with cobicistat; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with cobicistat may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [51664] [58000] Colistimethate, Colistin, Polymyxin E: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Colistin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Dabrafenib: (Major) Avoid concomitant use of dabrafenib and hormonal contraceptives; decreased hormonal contraceptive concentrations and loss of efficacy may occur. Use of an alternative non-hormonal contraceptive method of birth control is recommended during treatment for 2 weeks after the last dose of dabrafenib. Dabrafenib is a moderate CYP3A4 inducer and many hormonal contraceptive are CYP3A4 substrates. [54802] Dalbavancin: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Dapagliflozin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Dapagliflozin; Metformin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] Dapagliflozin; Saxagliptin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Daptomycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Darunavir: (Major) Drospirenone may be administered concurrently with darunavir; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with darunavir may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [28142] [49523] [56579] Darunavir; Cobicistat: (Major) Drospirenone may be administered concurrently with cobicistat; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with cobicistat may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [51664] [58000] (Major) Drospirenone may be administered concurrently with darunavir; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with darunavir may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [28142] [49523] [56579] Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Major) Drospirenone may be administered concurrently with cobicistat; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with cobicistat may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [51664] [58000] (Major) Drospirenone may be administered concurrently with darunavir; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with darunavir may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [28142] [49523] [56579] Deferasirox: (Moderate) Counsel patients to use non-hormonal methods of contraception during treatment with deferasirox. Deferasirox may induce the CYP3A4 metabolism of hormonal contraceptives; thereby decreasing their effectiveness. [31807] [42068] Delafloxacin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Delavirdine: (Minor) Delavirdine is a strong CYP3A4 inhibitor. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when CYP3A4 inhibitors are coadministered with drospirenone; estradiol. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. [28476] [31698] Demeclocycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Dicloxacillin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Doripenem: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Doxycycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Efavirenz: (Major) Patients should be advised to use a reliable method of barrier contraception in addition to oral contraceptives or non-oral combination contraceptives, including implantable etonogestrel, while using efavirenz. Efavirenz has no effect on ethinyl estradiol concentrations, but levels of progestins (norelgestromin and levonorgestrel) can be markedly decreased. Norelgestromin Cmax and AUC decreased by 46% and 64%, respectively. Levonorgestrel Cmax and AUC decreased bu 80% and 83%, respectively. There have been post-marketing reports of contraceptive failure with implantable etonogestrel in efavirenz-exposed patients. Decreased exposure of etonogestrel may be expected. There are no effects of ethinyl estradiol/norgestimate on efavirenz plasma concentrations. [28442] [46638] Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Patients should be advised to use a reliable method of barrier contraception in addition to oral contraceptives or non-oral combination contraceptives, including implantable etonogestrel, while using efavirenz. Efavirenz has no effect on ethinyl estradiol concentrations, but levels of progestins (norelgestromin and levonorgestrel) can be markedly decreased. Norelgestromin Cmax and AUC decreased by 46% and 64%, respectively. Levonorgestrel Cmax and AUC decreased bu 80% and 83%, respectively. There have been post-marketing reports of contraceptive failure with implantable etonogestrel in efavirenz-exposed patients. Decreased exposure of etonogestrel may be expected. There are no effects of ethinyl estradiol/norgestimate on efavirenz plasma concentrations. [28442] [46638] Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Patients should be advised to use a reliable method of barrier contraception in addition to oral contraceptives or non-oral combination contraceptives, including implantable etonogestrel, while using efavirenz. Efavirenz has no effect on ethinyl estradiol concentrations, but levels of progestins (norelgestromin and levonorgestrel) can be markedly decreased. Norelgestromin Cmax and AUC decreased by 46% and 64%, respectively. Levonorgestrel Cmax and AUC decreased bu 80% and 83%, respectively. There have been post-marketing reports of contraceptive failure with implantable etonogestrel in efavirenz-exposed patients. Decreased exposure of etonogestrel may be expected. There are no effects of ethinyl estradiol/norgestimate on efavirenz plasma concentrations. [28442] [46638] Elagolix: (Major) During use of elagolix, females of childbearing potential should use non-hormonal methods of contraception for the duration of treatment and for 28 days following the discontinuation of therapy. Estrogen-containing injectable, implantable, transdermal, vaginal or oral contraceptives are expected to reduce the efficacy of elagolix. The effect of progestin-only contraceptives on elagolix is not known. However, elagolix is a weak to moderate inducer of CYP3A4, and many estrogens and progestins are metabolized via this enzyme. Thus, elagolix may decrease plasma concentrations of hormonal contraceptives. Coadministration of elagolix 200 mg twice daily and a combined oral contraceptive (COC) containing 0.1 mg levonorgestrel decreases the plasma concentrations of levonorgestrel by 27%, potentially affecting contraceptive efficacy. Coadministration of elagolix with COCs containing norethindrone acetate did not show reduction in plasma concentrations of norethindrone. Elagolix may also increase contraceptive concentrations. Coadministration of a COC (containing 20 mcg ethinyl estradiol/0.1 mg levonorgestrel) following administration of elagolix 200 mg twice daily for 14 days increases the plasma ethinyl estradiol concentration by 2.2-fold compared to this COC alone; this may lead to increased risk of ethinyl estradiol-related adverse events including thromboembolic disorders and vascular events. [63387] Elagolix; Estradiol; Norethindrone acetate: (Major) During use of elagolix, females of childbearing potential should use non-hormonal methods of contraception for the duration of treatment and for 28 days following the discontinuation of therapy. Estrogen-containing injectable, implantable, transdermal, vaginal or oral contraceptives are expected to reduce the efficacy of elagolix. The effect of progestin-only contraceptives on elagolix is not known. However, elagolix is a weak to moderate inducer of CYP3A4, and many estrogens and progestins are metabolized via this enzyme. Thus, elagolix may decrease plasma concentrations of hormonal contraceptives. Coadministration of elagolix 200 mg twice daily and a combined oral contraceptive (COC) containing 0.1 mg levonorgestrel decreases the plasma concentrations of levonorgestrel by 27%, potentially affecting contraceptive efficacy. Coadministration of elagolix with COCs containing norethindrone acetate did not show reduction in plasma concentrations of norethindrone. Elagolix may also increase contraceptive concentrations. Coadministration of a COC (containing 20 mcg ethinyl estradiol/0.1 mg levonorgestrel) following administration of elagolix 200 mg twice daily for 14 days increases the plasma ethinyl estradiol concentration by 2.2-fold compared to this COC alone; this may lead to increased risk of ethinyl estradiol-related adverse events including thromboembolic disorders and vascular events. [63387] Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Major) Drospirenone may be administered concurrently with cobicistat; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with cobicistat may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [51664] [58000] (Moderate) Consider the benefits and risk of administering elvitegravir with ethinyl estradiol; norgestimate and other combination oral contraceptives. Concurrent use may result in elevated norgestimate and reduced ethinyl estradiol serum concentrations. Risk associated with these altered concentrations may include increased insulin resistance, dyslipidemia, acne, and venous thrombosis. Consider alternative non-hormonal methods of contraception, such as condoms, to prevent unwanted pregnancy and transmission of HIV/AIDS. [46638] [58001] Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Drospirenone may be administered concurrently with cobicistat; however, close clinical monitoring for adverse events such as hyperkalemia is recommended. Taking drospirenone with cobicistat may increase drospirenone serum concentrations. Instruct women to report adverse events to their prescribers. Further, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive these drugs together should use an additional barrier method of contraception such as condoms. [51664] [58000] (Moderate) Consider the benefits and risk of administering elvitegravir with ethinyl estradiol; norgestimate and other combination oral contraceptives. Concurrent use may result in elevated norgestimate and reduced ethinyl estradiol serum concentrations. Risk associated with these altered concentrations may include increased insulin resistance, dyslipidemia, acne, and venous thrombosis. Consider alternative non-hormonal methods of contraception, such as condoms, to prevent unwanted pregnancy and transmission of HIV/AIDS. [46638] [58001] Empagliflozin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [60134] Empagliflozin; Linagliptin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [60134] (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents, such as linagliptin, should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Empagliflozin; Linagliptin; Metformin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [60134] (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents, such as linagliptin, should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] Empagliflozin; Metformin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [60134] (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] Encorafenib: (Major) Avoid coadministration of encorafenib and hormonal contraceptives due to the potential for loss of contraceptive efficacy. Advise females of reproductive potential to use an effective, non-hormonal method of contraception during treatment and for 2 weeks after the final dose of encorafenib. Encorafenib can cause fetal harm when administered during pregnancy. [63317] Enzalutamide: (Major) Avoid coadministration of enzalutamide with progestins if used for contraception; consider an alternate or additional form of contraception. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of enzalutamide. Patients taking hormonal replacement therapy may need to be monitored for reduced clinical effect while on enzalutamide, with dose adjustments made based on clinical efficacy. Higher-dose hormonal regimens may be indicated where acceptable or applicable. Women taking hormonal replacement and enzalutamide should report breakthrough bleeding, hot flashes, or other symptoms to their prescribers. Progestins are substrates of CYP3A4 and enzalutamide is a strong CYP3A4 inducer. Concurrent administration of enzalutamide with progestins, oral contraceptives, or non-oral combination contraceptives may reduce hormonal concentrations. This interaction does not apply to vaginal preparations of progesterone (e.g., Crinone, Endometrin). [51727] [63694] Eplerenone: (Moderate) Drospirenone has antimineralocorticoid effects and may increase serum potassium, therefore concurrent use of eplerenone may increase the risk of hyperkalemia, especially in the presence of renal impairment. Monitor serum potassium during the 1st month of drospirenone treatment if eplerenone is used concurrently and thereafter as clinically indicated. Also monitor for any changes in blood pressure, fluid retention, or renal function. [31698] [40219] [41929] [42068] [42851] Eravacycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ertapenem: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ertugliflozin: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Ertugliflozin; Metformin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Ertugliflozin; Sitagliptin: (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Erythromycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Eslicarbazepine: (Major) Coadministration of eslicarbazepine with oral contraceptives may result in contraceptive failure. Coadministration of eslicarbazepine and ethinyl estradiol and levonorgestrel has resulted in decreased plasma concentrations of these hormones. Instruct females of child-bearing potential to use additional or non-hormonal contraception during therapy with eslicarbazepine and after treatment has been discontinued for at least one menstrual cycle. [56436] Etravirine: (Major) Women taking both progestins and etravirine should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed etravirine. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for one month after discontinuation of etravirine. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and etravirine is a strong CYP3A4 inducer. [33322] [33718] [57648] [63694] Exenatide: (Moderate) Separate the administration times of exenatide and estrogen and progestin containing oral contraceptives. Advise patients to take estrogen and progestin containing oral contraceptives at least 1 hour before exenatide. Exenatide slows gastric emptying and simultaneous coadministration may reduce the rate and extent of estrogen and progestin oral absorption which may reduce efficacy. Additionally, estrogens can impair glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day. [30585] [44456] [48491] [62853] Felbamate: (Major) Based on very limited data, it appears felbamate can accelerate the clearance of the estrogen component of some oral contraceptives. Patients who experience breakthrough bleeding while receiving these drugs together should notify their prescribers. An alternate or additional form of contraception should be used during concomitant treatment. Additionally, patients taking non-oral combination contraceptives or estrogens or progestins for hormone replacement therapy may also experience reduced clinical efficacy; dosage adjustments may be necessary. [7006] [7241] Fidaxomicin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Finerenone: (Moderate) Monitor serum potassium concentrations closely if finerenone and drospirenone are used together. Concomitant use may increase the risk of hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia in high-risk patients, comparable to 25 mg of spironolactone. [31698] [40219] [42068] [66793] Flibanserin: (Moderate) The concomitant use of flibanserin and multiple weak CYP3A4 inhibitors, including oral contraceptives, may increase flibanserin concentrations, which may increase the risk of flibanserin-induced adverse reactions. Therefore, patients should be monitored for hypotension, syncope, somnolence, or other adverse reactions, and the risks of combination therapy with multiple weak CYP3A4 inhibitors and flibanserin should be discussed with the patient. In one study of 24 healthy women, the effect of 100 mg flibanserin once daily for 2 weeks on the pharmacokinetics of a single dose of ethinyl estradiol 30 mcg/levonorgestrel 150 mcg was evaluated. Flibanserin increased the AUC and Cmax of ethinyl estradiol by 1.09-fold and 1.1-fold, respectively. Flibanserin decreased the levonorgestrel AUC by 1.06-fold. During pre-marketing evaluation of flibanserin, patients who reported using oral contraceptives had a greater incidence of CNS effects than flibenserin-treated patients who did not report oral contraceptive use, including dizziness (13.4% vs. 9.9%), somnolence (12.3% vs. 10.6%), and fatigue (11.4% vs. 7.5%). [60099] Fluvoxamine: (Minor) Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when CYP3A4 inhibitors, such as fluvoxamine, are coadministered with drospirenone; estradiol. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take CYP3A4 inhibitors long-term and concomitantly. [31698] [47184] [54631] [54632] Fosamprenavir: (Major) Avoid concurrent use of contraceptives and hormone replacement therapies (HRT) containing progestins with fosamprenavir. Alternative methods of non-hormonal contraception are recommended. Concomitant use may decrease the efficacy of both the progestin and fosamprenavir, which could lead to loss of virologic response and possible viral resistance. Additionally, there is an increased risk of transaminase elevations during concurrent use of progestins and fosamprenavir boosted with ritonavir. [29012] [68183] Gemifloxacin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used with antibiotics. Oral contraceptives (estrogen/progesterone) reduced the AUC and Cmax of gemifloxacin by 19% and 12%, respectively. These reductions are considered to be clinically insignificant. Gemifloxacin did not affect the pharmacokinetics of an ethinyl estradiol/levonorgestrel oral contraceptive product in healthy females. It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28424] [28482] [28509] Gentamicin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Glimepiride: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Glimepiride; Rosiglitazone: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Glipizide: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Glipizide; Metformin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Glyburide: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Glyburide; Metformin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Glycylcyclines: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Grapefruit juice: (Minor) Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. Strong CYP3A4 inhibitors include grapefruit juice. Grapefruit juice contains a furano-coumarin compound, 6,7-dihydroxybergamottin that inhibits CYP3A4 in enterocytes. In addition, grapefruit juice has been reported to decrease the metabolism of some estrogens. Estrogen levels may increase by up to 30%. The clinical significance of the interaction is unknown. It is possible that estrogen induced side effects could be increased in some individuals. Patients should be advised to not significantly alter their grapefruit juice ingestion. [29087] [31698] [58104] Griseofulvin: (Major) The concurrent use of griseofulvin and oral contraceptives can reduce contraceptive efficacy and result in an unintended pregnancy and/or breakthrough bleeding. This risk is particularly serious because griseofulvin is contraindicated during pregnancy due to the risk of teratogenic and abortifacient effects. An alternate or additional form of contraception should be used during concomitant treatment and continued for 1 month after griseofulvin discontinuation. If these drugs are used together, counsel the patient about the risk of pregnancy and teratogenic effects, and instruct the patient to notify the prescriber if they experience breakthrough bleeding while receiving these drugs together. Additionally, patients taking non-oral combination contraceptives or progestins for hormone replacement therapy may also experience reduced clinical efficacy. [28509] [45723] [58441] [59800] Heparin: (Minor) Chronic heparin therapy may predispose a patient to develop hyperkalemia; this risk may be increased in patients receiving drospirenone concomitantly. Monitoring of serum potassium during the 1st month of concurrent therapy with drospirenone is recommended. [4716] Hydantoins: (Major) Women taking both progestins and hydantoins should report breakthrough bleeding to their prescribers. If used for contraception, an alternate or additional form of non-hormonal contraception should be considered in patients prescribed hydantoins. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of hydantoins. Patients taking progestins for other indications may need to be monitored for reduced clinical effect while on hydantoins, with dose adjustments made based on clinical efficacy. Hydantoins are strong hepatic CYP450 inducers. Concurrent administration may increase progestin elimination This interaction does not apply to vaginal preparations of progesterone (e.g., Crinone, Endometrin). [28535] [28771] [42126] [48201] [57036] [57588] [57648] [63694] Idelalisib: (Moderate) Idelalisib is a strong CYP3A inhibitor, and ethinyl estradiol (EE) is a CYP3A substrate. Use caution in dose selection, as the hormonal side effects of ethinyl estradiol may be increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib. Females of reproductive potential should avoid becoming pregnant during idelalisib therapy, using effective contraception during treatment and for at least 1 month after the last dose. Thus, use idelalisib with caution in combination with any combination oral contraceptives, most of which contain EE or mestranol (which is converted to EE). In addiiton, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. [31698] [47343] [4744] [57675] Imipenem; Cilastatin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Imipenem; Cilastatin; Relebactam: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Indinavir: (Major) Indinavir may decrease the metabolism of oral contraceptives and non-oral combination contraceptives. Women receiving hormonal contraceptives and anti-retroviral protease inhibitors (PIs), such as indinavir, should be instructed to report any breakthrough bleeding or other adverse effects to their prescribers. It may be prudent for women who receive hormonal contraceptives with PIs that include ritonavir as a booster to use an additional method of contraception to protect against unwanted pregnancy. Furthermore, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive hormonal contraceptives with PIs should use an additional barrier method of contraception such as condoms. In women receiving oral contraceptives containing drospirenone, consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors, such as indinavir, long-term and concomitantly. Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. [28142] [49523] [56579] Insulin Glargine; Lixisenatide: (Moderate) Separate the administration times of lixisenatide and estrogen and progestin containing oral contraceptives. Advise patients to take estrogen and progestin containing oral contraceptives at least 1 hour before or 11 hours after lixisenatide. Lixisenatide slows gastric emptying and simultaneous coadministration may reduce the rate and extent of estrogen and progestin oral absorption which may reduce efficacy. Additionally, estrogens can impair glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day. [30585] [48491] [61024] [62853] Insulins: (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [60172] Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Major) Women taking both progestins and rifampin should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed rifampin. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for one month after discontinuation of rifampin. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and rifampin is a strong CYP3A4 inducer. [30314] [33322] [57648] Isoniazid, INH; Rifampin: (Major) Women taking both progestins and rifampin should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed rifampin. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for one month after discontinuation of rifampin. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and rifampin is a strong CYP3A4 inducer. [30314] [33322] [57648] Itraconazole: (Moderate) Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Itraconazole is a strong CYP3A4 inhibitor and may increase drospirenone concentrations. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. [27982] [29036] [31698] [41929] [42851] Ivosidenib: (Major) Consider alternative methods of contraception in patients receiving ivosidenib. Coadministration may decrease the concentrations of hormonal contraceptives. [63368] Kanamycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Ketoconazole: (Moderate) Monitor for an increase in drospirenone-related adverse effects if coadministered with ketoconazole. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take drospirenone and ketoconazole long-term. Drospirenone is a CYP3A4 substrate that has antimineralocorticoid effects; the progestin may increase serum potassium. Ketoconazole is a strong inhibitor of CYP3A4; coadministration of ketoconazole with drospirenone resulted in a moderate increase of drospirenone exposure. [27982] [40219] [41929] [46132] [64244] [67231] Lamotrigine: (Moderate) Patients taking progestin hormones for contraception may consider an alternate or additional form of contraception, such as nonhormonal and/or barrier methods, during and for at least 1 month after discontinuation of lamotrigine. Higher-dose hormonal regimens may also be considered. Patients taking these hormones for other indications may need to be monitored for reduced clinical effect while on lamotrigine with dose adjustments made based on clinical efficacy. The AUC and Cmax of levonorgestrel decreased by 19% and 12%, respectively, among 16 volunteers during concurrent use with lamotrigine 300 mg/day. Serum progesterone concentrations did not suggest ovulation, however, serum FSH, LH, and estradiol concentrations suggested some loss of suppression of the hypothalamic-pituitary-ovarian axis. [28451] [44123] [48201] Lansoprazole; Amoxicillin; Clarithromycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. Strong CYP3A4 inhibitors include clarithromycin. [28238] [28482] [28509] [31698] [34329] Lefamulin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Leflunomide: (Moderate) Carefully consider the type and dose of oral contraceptives in patients taking leflunomide.Leflunomide may increase the effects of oral contraceptives. Following oral administration, leflunomide is metabolized to an active metabolite, teriflunomide, which is responsible for essentially all of leflunomide's in vivo activity. Following repeated teriflunomide doses, mean ethinyl estradiol Cmax and AUC increased 1.58- and 1.54-fold, respectively. Levonorgestrel Cmax increased 1.33-fold and AUC 1.41-fold during coadministration. [49634] Lesinurad: (Major) Lesinurad induces CYP3A4, which may reduce the concentrations of estrogen and progestin hormones. Hormonal contraceptives may not be reliable when coadministered with lesinurad. Females taking hormonal-based birth control should use additional non-hormonal methods and not rely solely on hormonal contraceptive methods when taking lesinurad. Hormonal contraceptives include combination oral contraceptives, non-oral combination contraceptives, and contraceptives containing only progestins and includes oral, injectable, transdermal, vaginal inserts, and implantable forms of hormonal birth control. Lesinurad may also reduce the effectiveness of other estrogens or progestins. Patients taking these hormones for other indications may need to be monitored for reduced clinical effect while on lesinurad, with adjustments made based on clinical efficacy. [60473] Lesinurad; Allopurinol: (Major) Lesinurad induces CYP3A4, which may reduce the concentrations of estrogen and progestin hormones. Hormonal contraceptives may not be reliable when coadministered with lesinurad. Females taking hormonal-based birth control should use additional non-hormonal methods and not rely solely on hormonal contraceptive methods when taking lesinurad. Hormonal contraceptives include combination oral contraceptives, non-oral combination contraceptives, and contraceptives containing only progestins and includes oral, injectable, transdermal, vaginal inserts, and implantable forms of hormonal birth control. Lesinurad may also reduce the effectiveness of other estrogens or progestins. Patients taking these hormones for other indications may need to be monitored for reduced clinical effect while on lesinurad, with adjustments made based on clinical efficacy. [60473] Levofloxacin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Levoketoconazole: (Moderate) Monitor for an increase in drospirenone-related adverse effects if coadministered with ketoconazole. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take drospirenone and ketoconazole long-term. Drospirenone is a CYP3A4 substrate that has antimineralocorticoid effects; the progestin may increase serum potassium. Ketoconazole is a strong inhibitor of CYP3A4; coadministration of ketoconazole with drospirenone resulted in a moderate increase of drospirenone exposure. [27982] [40219] [41929] [46132] [64244] [67231] Linagliptin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents, such as linagliptin, should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Linagliptin; Metformin: (Minor) Estrogens, progestins, or oral contraceptives can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving > 50 mcg of ethinyl estradiol per day. The presence or absence of a concomitant progestin may influence the significance of this effect. Patients receiving antidiabetic agents, such as linagliptin, should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] Lincomycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Lincosamides: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Linezolid: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Lixisenatide: (Moderate) Separate the administration times of lixisenatide and estrogen and progestin containing oral contraceptives. Advise patients to take estrogen and progestin containing oral contraceptives at least 1 hour before or 11 hours after lixisenatide. Lixisenatide slows gastric emptying and simultaneous coadministration may reduce the rate and extent of estrogen and progestin oral absorption which may reduce efficacy. Additionally, estrogens can impair glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day. [30585] [48491] [61024] [62853] Lomitapide: (Major) Concomitant use of lomitapide and oral contraceptives may significantly increase the serum concentration of lomitapide. Therefore, the lomitapide dose should not exceed 30 mg/day PO during concurrent use. Oral Contraceptives are weak CYP3A4 inhibitors; the exposure to lomitapide is increased by approximately 2-fold in the presence of weak CYP3A4 inhibitors. In addition, females of reproductive potential must use effective contraception during lomitapide therapy. Because vomiting and diarrhea have been frequently reported during lomitapide therapy and hormone absorption from oral contraceptives may be incomplete in the presence of vomiting or diarrhea, warn patients that the use of additional contraceptive methods is warranted if vomiting or diarrhea occur. [52698] Lonafarnib: (Moderate) Monitor for an increase in drospirenone-related adverse effects if coadministered with lonafarnib. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take drospirenone and lonafarnib long-term. Drospirenone is a CYP3A4 substrate that has antimineralocorticoid effects which may increase serum potassium; lonafarnib is a strong inhibitor of CYP3A4 and may increase drospirenone concentrations. Coadministration with another strong CYP3A4 inhibitor resulted in a moderate increase of drospirenone exposure. [64244] [66129] Lorlatinib: (Major) Women taking both progestins and lorlatinib should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed lorlatinib. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of lorlatinib. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and lorlatinib is a moderate CYP3A4 inducer. [33322] [57648] [63732] Lumacaftor; Ivacaftor: (Major) Avoid concomitant use of hormonal contraceptives and lumacaftor; ivacaftor, unless the benefits outweigh the risks. Lumacaftor; ivacaftor may decrease hormonal contraceptive exposure, reducing efficacy. When coadministered with lumacaftor; ivacaftor, hormonal contraceptives are not a reliable method of effective contraception; instruct patients on alternative methods of birth control. In addition, concomitant use may increase the incidence of menstruation-associated adverse reactions (e.g., amenorrhea, dysmenorrhea, menorrhagia). [59891] Mafenide: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Mavacamten: (Major) Patients taking both drospirenone and mavacamten should report breakthrough vaginal bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed mavacamten. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 4 months after discontinuation of mavacamten. For patients on hormone replacement treatments (HRT) with drospirenone, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Drospirenone is a CYP3A substrate and mavacamten is a moderate CYP3A inducer. [64244] [67543] Meglitinides: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [7053] Meropenem: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Meropenem; Vaborbactam: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Metformin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] Metformin; Repaglinide: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] Metformin; Rosiglitazone: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Metformin; Saxagliptin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Metformin; Sitagliptin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Methohexital: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Metronidazole: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Mifepristone: (Major) Mifepristone is a progesterone-receptor antagonist and will interfere with the effectiveness of hormonal contraceptives. Therefore, non-hormonal contraceptive methods should be used in Cushing's patients taking mifepristone. [48697] Miltefosine: (Moderate) Miltefosine-induced vomiting and/or diarrhea may affect absorption of oral contraceptives and compromise their efficacy. If vomiting or diarrhea occur during miltefosine therapy, advise females to use an additional non-oral method of effective contraception. [56867] Minocycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Mitotane: (Major) Use caution if mitotane and drospirenone are used concomitantly, including combination products such as drospirenone; estradiol, drospirenone; ethinyl estradiol, and drospirenone; ethinyl estradiol; levomefolate. If coadministration is necessary, monitor for decreased efficacy of products containing drospirenone and consider an alternate or additional form of contraception. The alternative or additional contraceptive agent may need to be continued for one month after discontinuation of mitotane. Mitotane is a strong CYP3A4 inducer. Although CYP3A4 is a minor elimination pathway for drospirenone, drospirenone is only available in combination with ethinyl estradiol, which is primarily metabolized by CYP3A4. Coadministration may result in decreased plasma concentrations of oral contraceptives. [41934] [42068] Mivacurium: (Moderate) Plasma cholinesterase activity may be diminished by chronic administration of oral contraceptives; consider the possibility of prolonged neuromuscular block after administration of mivacurium in patients with reduced plasma cholinesterase activity. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration. [42613] [65534] Mobocertinib: (Major) Women taking both progestins and mobocertinib should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed mobocertinib. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for one month after discontinuation of mobocertinib. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A substrates and mobocertinib is a weak CYP3A inducer. [33322] [57648] [63694] [66990] Modafinil: (Major) Modafinil may cause failure of oral contraceptives or hormonal contraceptive-containing implants or devices due to induction of CYP3A4 isoenzyme metabolism of the progestins in these products. An alternative method or an additional method of contraception should be utilized during modafinil therapy and continued for one month after modafinil discontinuation. If these drugs are used together, monitor patients for a decrease in clinical effects; patients should report breakthrough bleeding to their prescriber. Dosage adjustments may be necessary. [4718] [4744] [5259] Morphine: (Moderate) Combination oral contraceptives have been shown to decrease plasma concentrations of morphine, due to induction of conjugation. Monitor for decreased efficacy of morphine. [43307] [58441] Morphine; Naltrexone: (Moderate) Combination oral contraceptives have been shown to decrease plasma concentrations of morphine, due to induction of conjugation. Monitor for decreased efficacy of morphine. [43307] [58441] Moxifloxacin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28423] [28482] [28509] Nafcillin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Nefazodone: (Minor) Nefazodone is a strong CYP3A4 inhibitor. Serum estrogen concentrations and estrogenic-related side effects (e.g., nausea, breast tenderness) may potentially increase when CYP3A4 inhibitors are coadministered with drospirenone; estradiol. An interaction has been reported clinically, but more study is needed to determine the clinical significance of this interaction in the general population. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. [31698] Nelfinavir: (Major) Nelfinavir may decrease the metabolism of oral contraceptives and non-oral combination contraceptives. Women receiving hormonal contraceptives and anti-retroviral protease inhibitors (PIs), such as nelfinavir, should be instructed to report any breakthrough bleeding or other adverse effects to their prescribers. It may be prudent for women who receive hormonal contraceptives with PIs that include ritonavir as a booster to use an additional method of contraception to protect against unwanted pregnancy. Furthermore, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive hormonal contraceptives with PIs should use an additional barrier method of contraception such as condoms. In women receiving oral contraceptives containing drospirenone, consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors, such as nelfinavir, long-term and concomitantly. Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. [28142] [49523] [56579] Neomycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Nevirapine: (Moderate) Nevirapine may decrease plasma concentrations of oral contraceptives and non-oral combination contraceptives (i.e., ethinyl estradiol and norethindrone). However despite lower exposures, literature suggests that use of nevirapine has no effect on pregnancy rates among HIV-infected women on combined oral contraceptives. Thus, the manufacturer states that no dose adjustments are needed when these drugs are used for contraception in combination with nevirapine. When these oral contraceptives are used for hormone replacement and given with nevirapine, the therapeutic effect of the hormonal therapy should be monitored. [42456] Nitrofurantoin: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Nonsteroidal antiinflammatory drugs: (Minor) Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Other drugs that may have additive effects on serum potassium with drospirenone include chronic treatment with NSAIDs, and monitoring of serum potassium in the 1st month of concurrent therapy is recommended. [4716] Ofloxacin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Omadacycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Omeprazole; Amoxicillin; Rifabutin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Oritavancin: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Oxacillin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Oxcarbazepine: (Major) Progestins are susceptible to drug interactions with hepatic enzyme inducing drugs such as oxcarbazepine. Concurrent administration of oxcarbazepine progestins may increase the hormone's elimination. A high percentage of breakthrough bleeding has been reported in the literature from the combined use of oxcarbazepine and oral contraceptives; the results of one study demonstrated that the mean AUC of ethinyl estradiol/levonorgestrel was decreased by 52% when coadministered with oxcarbazepine. Women taking both hormones and hepatic enzyme-inducing drugs should report breakthrough bleeding to their prescribers. If used for contraception, an alternate or additional form of contraception should be considered in patients prescribed hepatic enzyme inducing drugs, or higher-dose hormonal regimens may be indicated where acceptable or applicable as pregnancy has been reported in patients taking the hepatic enzyme inducing drug phenytoin concurrently with hormonal contraceptives. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of the interacting medication. Additionally, epileptic women taking both anticonvulsants and OCs may be at higher risk of folate deficiency secondary to additive effects on folate metabolism; if oral contraceptive failure occurs, the additive effects could potentially heighten the risk of neural tube defects in pregnancy. Patients taking these hormones for other indications may need to be monitored for reduced clinical effect while on oxcarbazepine, with dose adjustments made based on clinical efficacy. [22005] [5307] [55436] [57046] [57048] [5749] [57648] [6300] Paromomycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Pegaspargase: (Major) Avoid the concomitant use of pegaspargase and oral hormonal contraceptives due to the potential for decreased contraceptive efficacy and risk of fetal harm from pegaspargase. Women of reproductive potential should use an effective non-hormonal method of birth control during therapy and for at least 3 months after the last pegaspargase dose. [61310] Penicillin G Benzathine: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillins and their derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use (i.e., amoxicillin, chloramphenicol, neomycin, nitrofurantoin, sulfonamides, etc.) may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Penicillin G Benzathine; Penicillin G Procaine: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillins and their derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use (i.e., amoxicillin, chloramphenicol, neomycin, nitrofurantoin, sulfonamides, etc.) may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Penicillin G Procaine: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillins and their derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use (i.e., amoxicillin, chloramphenicol, neomycin, nitrofurantoin, sulfonamides, etc.) may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Penicillin G: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillins and their derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use (i.e., amoxicillin, chloramphenicol, neomycin, nitrofurantoin, sulfonamides, etc.) may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Penicillin V: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillins and their derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use (i.e., amoxicillin, chloramphenicol, neomycin, nitrofurantoin, sulfonamides, etc.) may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Pentobarbital: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Pexidartinib: (Major) Avoid the concomitant use of pexidartinib and hormone-containing contraceptives; the effectiveness of hormonal contraceptives may be decreased resulting in contraceptive failure. Females of reproductive potential should avoid pregnancy during and for 1 month after treatment with pexidartinib. Advise these patients to use an effective, non-hormonal method of contraception. Pexidartinib is a moderate CYP3A inducer and many oral contraceptives are metabolized by CYP3A. [64535] Phenobarbital: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Phentermine; Topiramate: (Moderate) Topiramate may reduce the efficacy of progestins used in contraception or hormone replacement therapies. Reduced contraceptive efficacy can occur even in the absence of breakthrough bleeding. Dosages of hormone replacement products may need adjustment. Different or additional forms of contraception (e.g., non-hormonal contraceptives) may also be needed. In a pharmacokinetic interaction study, a combination oral contraceptive (containing norethindrone and ethinyl estradiol) administered with only topiramate at doses of 50 to 200 mg/day did not result in clinically significant alterations of AUC for either component of the oral contraceptive. Norethindrone pharmacokinetics were not significantly affected. Pregnancy has been reported in patients who are using hormonal-containing contraceptives and hepatic enzyme inducers. [22005] [28378] [33941] [48201] [57046] [57048] [57588] [57648] Pioglitazone: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Pioglitazone; Glimepiride: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Pioglitazone; Metformin: (Minor) Patients receiving antidiabetic agents like metformin should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. Progestins can impair glucose tolerance. [28550] [30585] [62853] (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Piperacillin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Piperacillin; Tazobactam: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Pitolisant: (Major) Advise patients to use an alternative, non-hormonal contraceptive during and for at least 21 days after discontinuation of pitolisant. Pitolisant is a weak CYP3A4 inducer and may decrease the plasma exposure of hormonal contraceptives resulting in decreased efficacy. [64562] Plazomicin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Polymyxin B: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Posaconazole: (Moderate) Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Posaconazole is a strong CYP3A4 inhibitor and may increase drospirenone concentrations. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. [27982] [29036] [31698] [32723] [34464] [34465] [41929] [42851] Potassium: (Moderate) Monitor serum potassium concentrations closely if potassium supplements and drospirenone are used together. Concomitant use may increase the risk of hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia in high-risk patients, comparable to 25 mg of spironolactone. [30272] [64244] Potassium-sparing diuretics: (Moderate) Monitor serum potassium concentration during concomitant drospirenone and potassium-sparing diuretic use due to increased risk for hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia. [31698] [40219] [41929] [42068] [42851] Pramlintide: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [7053] Prasterone, Dehydroepiandrosterone, DHEA (Dietary Supplements): (Moderate) Either additive or antagonistic effects could potentially occur if prasterone is combined with progestins. [2455] Prasterone, Dehydroepiandrosterone, DHEA (FDA-approved): (Moderate) Either additive or antagonistic effects could potentially occur if prasterone is combined with progestins. [2455] Pretomanid: (Major) Avoid coadministration of pretomanid with oral contraceptives, especially in patients with impaired hepatic function, due to increased risk for hepatotoxicity. Monitor for evidence of hepatotoxicity if coadministration is necessary. If new or worsening hepatic dysfunction occurs, discontinue hepatotoxic medications. [63549] [64561] Primidone: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Rifampin: (Major) Women taking both progestins and rifampin should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed rifampin. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for one month after discontinuation of rifampin. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and rifampin is a strong CYP3A4 inducer. [30314] [33322] [57648] Rifapentine: (Major) Women taking both progestins and rifapentine should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed rifapentine. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for one month after discontinuation of rifapentine. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and rifapentine is a strong CYP3A4 inducer. [33322] [57648] [65685] Riluzole: (Moderate) Monitor patients for increased riluzole-related adverse events, such as gastrointestinal symptoms and elevated hepatic enzymes, when hormonal contraceptives are prescribed concurrently. Serum concentrations of riluzole, a CYP1A2 substrate, may increase when oral contraceptives, moderate CYP1A2 inhibitors, are used concurrently. In vitro findings suggest an increase in riluzole exposure is likely when a CYP1A2 inhibitor is given. [29747] [57048] Roflumilast: (Moderate) Coadminister oral contraceptives containing gestodene and ethinyl estradiol and roflumilast cautiously, as the combination has resulted in increased drug exposure to roflumilast in pharmacokinetic study. In an open-label crossover study in 20 healthy adult volunteers, coadministration of a single dose of oral roflumilast 500 mcg with repeated doses of a fixed combination oral contraceptive containing 0.075 mg gestodene and 0.03 mg ethinyl estradiol to steady state resulted in a 38% increase in Cmax of roflumilast and a 12% decrease in Cmax of the active metabolite roflumilast N-oxide. Roflumilast and roflumilast N-oxide AUCs were increased by 51% and 14%, respectively. A similar interaction is expected with oral contraceptives and ethinyl estradiol; etonogestrel. [43551] Rosiglitazone: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Rufinamide: (Major) Coadministration of hormonal contraceptives with rufinamide may reduce hormone concentrations and therefore reduce the clinical efficacy of hormonal contraceptives. If coadministration is necessary, recommend patients use additional non-hormonal forms of contraception. Hormonal contraceptives are metabolized by CYP3A4 and rufinamide is a weak CYP3A4 inducer. [34590] Saquinavir: (Minor) In women receiving oral contraceptives containing drospirenone, consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors, such as saquinavir, long-term and concomitantly. Drospirenone has antimineralocorticoid effects, including the potential for hyperkalemia in high-risk patients. [28995] [42068] Sarilumab: (Moderate) Utilize caution with concomitant use of sarilumab and CYP3A4 substrate drugs, such as combined hormonal oral contraceptives, where a decrease in effectiveness is undesirable. Inhibition of IL-6 signaling by sarilumab may restore CYP450 activities to higher levels leading to increased metabolism of drugs that are CYP450 substrates as compared to metabolism prior to treatment. This effect on CYP450 enzyme activity may persist for several weeks after stopping sarilumab. In vitro, sarilumab has the potential to affect expression of multiple CYP enzymes, including CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. [61976] Saxagliptin: (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Secobarbital: (Moderate) Barbiturates can accelerate the hepatic clearance of progestins. For hormonal contraceptives, this interaction could result in unintended pregnancy or breakthrough bleeding. For patients regularly taking a barbiturate, an alternative or back-up method of contraception may be advisable to ensure contraceptive reliability during the use of the barbiturate, and for 1 month following the discontinuation of barbiturate use. The exception is the use of levonorgestrel progestin IUDs, which have not been reported to interact and appear to maintain reliable efficacy. Pregnancy has been reported during therapy with both estrogen- and/or progestin-based oral contraceptives in patients receiving barbiturates (e.g., phenobarbital). For patients taking progestins for other indications, like hormone replacement, monitor the patient for signs and symptoms of reduced therapeutic efficacy or need for dosage adjustment. [22005] [28502] [29653] [29821] [30802] [30858] [30890] [33322] [42126] [46375] [48201] [48254] [49996] [57048] [57271] [57649] [59800] [62899] Siltuximab: (Moderate) Caution is warranted when siltuximab is used in patients taking CYP3A4 substrates, such as oral contraceptives, in which a decreased effect would be undesirable. Cytochrome P450s in the liver are down regulated by infection and inflammation stimuli, including cytokines such as interleukin-6 (IL-6). Inhibition of IL-6 signaling by siltuximab may restore CYP450 activities to higher levels leading to increased metabolism of drugs that are CYP450 substrates as compared to metabolism prior to treatment. The effect of siltuximab on CYP450 enzyme activity can persist for several weeks after stopping therapy. [57062] Simvastatin; Sitagliptin: (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Sitagliptin: (Minor) Progestins can decrease the hypoglycemic effects of antidiabetic agents by impairing glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for changes in diabetic control when hormone therapy is instituted or discontinued. [7347] Sotorasib: (Major) Women taking both drospirenone and sotorasib should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed sotorasib. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of sotorasib. For patients on hormone replacement treatments (HRT) with drospirenone, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Drospirenone is a CYP3A4 substrate and sotorasib is a moderate CYP3A4 inducer. [64244] [66700] Spironolactone: (Moderate) Monitor serum potassium concentration during concomitant drospirenone and potassium-sparing diuretic use due to increased risk for hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia. [31698] [40219] [41929] [42068] [42851] Spironolactone; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum potassium concentration during concomitant drospirenone and potassium-sparing diuretic use due to increased risk for hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia. [31698] [40219] [41929] [42068] [42851] St. John's Wort, Hypericum perforatum: (Major) As with other CYP3A4 inducers, St. John's wort may reduce the therapeutic efficacy of progestin-only contraceptives or other progestin-based hormonal therapies. Patients should report irregular menstrual bleeding or other hormone-related symptoms to their health care providers if they are taking St. John's wort concurrently with their hormones. Avoidance of St. John's wort is recommended. This interaction does not apply to vaginal preparations of progesterone (e.g., Crinone, Endometrin). [42126] [48201] [57202] [57588] [57648] [63694] Streptogramins: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. Additionally, dalfopristin; quinupristin is a major inhibitor of cytochrome P450 3A4 and may decrease the elimination of drugs metabolized by this enzyme including ethinyl estradiol and norethindrone. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. [28482] [28509] [31698] Streptomycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Succinylcholine: (Moderate) Plasma cholinesterase activity may be diminished by chronic administration of oral contraceptives; consider the possibility of prolonged neuromuscular block after administration of succinylcholine in patients with reduced plasma cholinesterase activity. The use of a peripheral nerve stimulator is strongly recommended to evaluate the level of neuromuscular blockade, to assess the need for additional doses of neuromuscular blocker, and to determine whether adjustments need to be made to the dose with subsequent administration. [42039] [65534] Sugammadex: (Major) If an oral contraceptive is taken the same day sugammadex is administered, the patient must use an additional, non-hormonal contraceptive method or back-up method of contraception for the next 7 days. Sugammadex may bind to progestogen, resulting in a decrease in progestogen exposure. The administration of a bolus dose of sugammadex results in actions that are essentially equivalent to missing one or more doses of contraceptives containing estrogen or progestogen, including combination oral contraceptives, non-oral combination contraceptives, or progestins. [60450] Sulfadiazine: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Sulfasalazine: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Sulfonamides: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Sulfonylureas: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Tazemetostat: (Major) Women taking both progestins and tazemetostat should report breakthrough bleeding to their prescribers. An alternate or additional form of contraception should be considered in patients prescribed tazemetostat. Higher-dose hormonal regimens may be indicated where acceptable or applicable. The alternative or additional contraceptive agent may need to be continued for 1 month after discontinuation of tazemetostat. For patients on hormone replacement treatments (HRT) with progestins, monitor for altered clinical response, such as increased hot flashes, vaginal dryness, changes in withdrawal bleeding, or other signs of decreased hormonal efficacy. Progestins are CYP3A4 substrates and tazemetostat is a weak CYP3A4 inducer. [33322] [57648] [64952] Tedizolid: (Moderate) It was previously thought that antibiotics may decrease the effectiveness of oral contraceptives containing estrogens due to stimulation of estrogen metabolism or a reduction in estrogen enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with oral contraceptives (OCs) and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma levels of oral contraceptives. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review of the subject concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances.Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Telavancin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Teriflunomide: (Moderate) Teriflunomide may increase the effects of oral contraceptives. Following consecutive teriflunomide doses, mean ethinyl estradiol Cmax and AUC increased 1.58- and 1.54-fold, respectively, during coadministration. Levonorgestrel Cmax increased 1.33-fold and AUC 1.41-fold during coadministration. Use caution when selecting the type and dose of oral contraceptives in patients taking teriflunomide. [51794] Tetracycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Thalidomide: (Moderate) Thalidomide and hormone contraceptives should be used cautiously due an increased risk of thromboembolism. The pharmacokinetic parameters of norethindrone/estradiol were not affected when a single dose of norethindrone 1 mg/estradiol 75 micrograms was administered in 10 healthy women who were receiving thalidomide 200 mg/day (at steady state levels). [49713] Thiazolidinediones: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [30585] [62853] Tigecycline: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Tinidazole: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Tipranavir: (Major) Tipranavir may decrease the metabolism of oral contraceptives and non-oral combination contraceptives. Women receiving hormonal contraceptives and anti-retroviral protease inhibitors (PIs), such as tipanavir, should be instructed to report any breakthrough bleeding or other adverse effects to their prescribers. It may be prudent for women who receive hormonal contraceptives with PIs that include ritonavir as a booster to use an additional method of contraception to protect against unwanted pregnancy. Furthermore, because hormonal contraceptives do not protect against the transmission of HIV/AIDS and other sexually transmitted diseases, women who receive hormonal contraceptives with PIs should use an additional barrier method of contraception such as condoms. In women receiving oral contraceptives containing drospirenone, consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors, such as tipranavir, long-term and concomitantly. Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. [28142] [49523] [56579] Tirzepatide: (Major) Advise patients receiving tirzepatide and oral contraceptives to switch to a non-oral contraceptive method or to add a barrier method of contraception for 4 weeks after initiation and for 4 weeks after each dose escalation of tirzepatide. Tirzepatide delays gastric emptying and may reduce the rate and extent of estrogen and progestin absorption which may reduce efficacy. Gastric emptying delays are greatest after the first dose of tirzepatide and diminish over time. Hormonal contraceptives that are not administered orally should not be affected. Additionally, estrogens can impair glucose tolerance. Changes in glucose tolerance occur more commonly in patients receiving 50 mcg or more of ethinyl estradiol (or equivalent) per day. [30585] [48491] [62853] [67631] Tizanidine: (Major) Avoid concomitant use of tizanidine and oral contraceptives as increased tizanidine exposure may occur. If use together is necessary, initiate tizanidine with a single 2 mg dose and increase by 2 to 4 mg/day based on clinical response. Discontinue tizanidine if hypotension, bradycardia, or excessive drowsiness occurs. A retrospective analysis of population pharmacokinetic data found that the clearance of tizanidine was 50% lower in females taking oral contraceptives compared to those not on oral contraceptives. [52430] Tobramycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Tocilizumab: (Moderate) Utilize caution with concomitant use of tocilizumab and CYP3A4 substrate drugs, such as combined hormonal oral contraceptives, where a decrease in effectiveness is undesirable. Inhibition of IL-6 signaling by tocilizumab may restore CYP450 activities to higher levels leading to increased metabolism of drugs that are CYP450 substrates as compared to metabolism prior to treatment. This effect on CYP450 enzyme activity may persist for several weeks after stopping tocilizumab. In vitro, tocilizumab has the potential to affect expression of multiple CYP enzymes, including CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. [38283] Tolazamide: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Tolbutamide: (Minor) Progestins can impair glucose tolerance. Patients receiving antidiabetic agents should be closely monitored for signs indicating changes in diabetic control when therapy with progestins is instituted or discontinued. [6266] Topiramate: (Moderate) Topiramate may reduce the efficacy of progestins used in contraception or hormone replacement therapies. Reduced contraceptive efficacy can occur even in the absence of breakthrough bleeding. Dosages of hormone replacement products may need adjustment. Different or additional forms of contraception (e.g., non-hormonal contraceptives) may also be needed. In a pharmacokinetic interaction study, a combination oral contraceptive (containing norethindrone and ethinyl estradiol) administered with only topiramate at doses of 50 to 200 mg/day did not result in clinically significant alterations of AUC for either component of the oral contraceptive. Norethindrone pharmacokinetics were not significantly affected. Pregnancy has been reported in patients who are using hormonal-containing contraceptives and hepatic enzyme inducers. [22005] [28378] [33941] [48201] [57046] [57048] [57588] [57648] Triamterene: (Moderate) Monitor serum potassium concentration during concomitant drospirenone and potassium-sparing diuretic use due to increased risk for hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia. [31698] [40219] [41929] [42068] [42851] Triamterene; Hydrochlorothiazide, HCTZ: (Moderate) Monitor serum potassium concentration during concomitant drospirenone and potassium-sparing diuretic use due to increased risk for hyperkalemia. Drospirenone has anti-mineralocorticoid activity, including the potential for hyperkalemia. [31698] [40219] [41929] [42068] [42851] Trimethoprim: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Tucatinib: (Moderate) Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take drospirenone and tucatinib long-term. Drospirenone is a CYP3A4 substrate that has antimineralocorticoid effects; the progestin may increase serum potassium. Tucatinib is a strong inhibitor of CYP3A4 and may increase drospirenone concentrations. [64244] [65295] Ulipristal: (Major) Avoid concurrent use of ulipristal and progestin-containing hormonal contraceptives or other progestins. Hormonal contraceptives may be started or resumed no sooner than 5 days after ulipristal treatment. Also, a reliable barrier method of contraception should be used during the same menstrual cycle in which ulipristal was administered (until the next menstrual period). Progestin-containing contraceptives may impair the ability of ulipristal to delay ovulation. Ulipristal may reduce the effectiveness of progestin-containing hormonal contraceptives by competitively binding at the progesterone receptor. [41569] [50623] Vancomycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Vonoprazan; Amoxicillin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] Vonoprazan; Amoxicillin; Clarithromycin: (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. [28482] [28509] (Moderate) It would be prudent to recommend alternative or additional contraception when oral contraceptives (OCs) are used in conjunction with antibiotics. It was previously thought that antibiotics may decrease the effectiveness of OCs containing estrogens due to stimulation of metabolism or a reduction in enterohepatic circulation via changes in GI flora. One retrospective study reviewed the literature to determine the effects of oral antibiotics on the pharmacokinetics of contraceptive estrogens and progestins, and also examined clinical studies in which the incidence of pregnancy with OCs and antibiotics was reported. It was concluded that the antibiotics ampicillin, ciprofloxacin, clarithromycin, doxycycline, metronidazole, ofloxacin, roxithromycin, temafloxacin, and tetracycline did not alter plasma concentrations of OCs. Antituberculous drugs (e.g., rifampin) were the only agents associated with OC failure and pregnancy. Based on the study results, these authors recommended that back-up contraception may not be necessary if OCs are used reliably during oral antibiotic use. Another review concurred with these data, but noted that individual patients have been identified who experienced significant decreases in plasma concentrations of combined OC components and who appeared to ovulate; the agents most often associated with these changes were rifampin, tetracyclines, and penicillin derivatives. These authors concluded that because females most at risk for OC failure or noncompliance may not be easily identified and the true incidence of such events may be under-reported, and given the serious consequence of unwanted pregnancy, that recommending an additional method of contraception during short-term antibiotic use may be justified. During long-term antibiotic administration, the risk for drug interaction with OCs is less clear, but alternative or additional contraception may be advisable in selected circumstances. Data regarding progestin-only contraceptives or for newer combined contraceptive deliveries (e.g., patches, rings) are not available. In addition, drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. Strong CYP3A4 inhibitors include clarithromycin. [28238] [28482] [28509] [31698] [34329] Voriconazole: (Moderate) Drospirenone has antimineralocorticoid effects; the progestin may increase serum potassium. Voriconazole is a strong inhibitor of CYP3A4 and may increase drospirenone concentrations. Consider monitoring serum potassium concentrations during the first month of dosing in high-risk patients who take strong CYP3A4 inhibitors long-term and concomitantly. [27982] [29036] [31698] [40219] [41929] [42851]
      Revision Date: 02/02/2023, 02:26:00 AM

      References

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      Monitoring Parameters

      • pap smear
      • pelvic exam
      • serum creatinine
      • serum potassium

      US Drug Names

      • Slynd
      ;