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Feb.05.2023

Ondansetron

Indications/Dosage

Labeled

  • chemotherapy-induced nausea/vomiting prophylaxis
  • post-operative nausea/vomiting (PONV) prophylaxis
  • radiation-induced nausea/vomiting prophylaxis

Off-Label

  • alcohol dependence
  • cyclic vomiting syndrome
  • gastroenteritis
  • nausea/vomiting
  • post-operative nausea/vomiting (PONV)
  • pregnancy-induced nausea/vomiting
  • pruritus
† Off-label indication

For chemotherapy-induced nausea/vomiting prophylaxis (CINV prophylaxis) and radiation-induced nausea/vomiting prophylaxis (RINV prophylaxis)

Intravenous dosage

Adults

0.15 mg/kg (150 mcg/kg) IV infused over 15 minutes beginning 30 minutes prior to the initiation of emetogenic chemotherapy. No single dose should exceed 16 mg/dose IV. Dosage may be repeated twice, administered 4 and 8 hours after the initial dose. NOTE: Since 2012, a 32 mg IV single-dose regimen is no longer indicated because of the risk of QT prolongation.[31266] [51100] [63197]

Infants 6 months and older, Children, and Adolescents

0.15 mg/kg IV infused over 15 minutes beginning 30 minutes prior to the initiation of chemotherapy and repeat 4 and 8 hours later (3 doses total). Max: 16 mg/dose.[31266] [52202] The American Society of Clinical Oncology (ASCO) recommends 0.15 mg/kg/dose (Max: 8 mg) twice daily during chemotherapy and for 2 days after completion, or give 1 to 2 hours before each fraction of radiation and for 1 day after completion for highly emetogenic therapy.[63197] Alternatively, ondansetron has been administered every 8 hours and continued for 1 to 5 days after completion of therapy.[49435] [52191] [52192] A single dose of 0.6 mg/kg IV was as effective as standard therapy (0.15 mg/kg/dose up to 8 mg every 4 hours for 4 doses) in a prospective, double-blind study in chemotherapy-naive pediatric oncology patients; however, the maximum dose in the study was 32 mg, which is no longer recommended because of dose-dependent QT prolongation.[52188]

Oral dosage

Adults receiving moderately emetogenic chemotherapy

8 mg PO twice daily. Give first dose 30 minutes before the start of emetogenic chemotherapy, with a subsequent dose 8 hours after the initial dose. Further doses may be given every 12 hours for 1 to 2 days after completion of chemotherapy.[49444]

Adults receiving highly emetogenic chemotherapy

24 mg dose PO once given 30 minutes before administration of single-day highly emetogenic chemotherapy, including cisplatin 50 mg/m2 or more. Multiday, single dose administration of ondansetron 24 mg has not been studied.[49444]

Adults receiving radiotherapy (general dosage)

8 mg PO 3 times daily.[49444]

Adults receiving total body irradiation

8 mg PO 1 to 2 hours prior to each fraction of radiotherapy each day.[49444]

Adults receiving daily fractionated radiotherapy or single high-dose fraction radiotherapy to the abdomen

Initially, 8 mg PO 1 to 2 hours prior to radiotherapy. Then, 8 mg PO every 8 hours after the first dose for 1 to 2 days following completion of radiotherapy.[49444]

Children and Adolescents 12 years and older

8 mg PO twice daily. Give the first dose 30 minutes prior to chemotherapy with a subsequent dose 8 hours after the initial dose. Further doses may be given every 12 hours for 1 to 2 days after completion of therapy.[49444] For radiation, give the first dose 1 to 2 hours prior to therapy. Further doses may be given every 8 to 12 hours for 1 to 5 days after completion of therapy.[63197] [52191] [52192] Alternatively, a single 24 mg PO dose may be given prior to chemotherapy.[52202]

Children 4 to 11 years

4 mg PO 3 times daily. Give the first dose 30 minutes prior to chemotherapy, with subsequent doses 4 and 8 hours after the initial dose. Further doses may be given every 8 hours for 1 to 2 days after completion of therapy.[49444] For radiation, give the first dose 1 to 2 hours prior to therapy. Further doses may be given every 8 hours for 1 to 5 days after completion of therapy.[52191] [52192] Alternatively, a single 12 mg PO dose may be given prior to chemotherapy.[52202]

Infants† and Children less than 4 years† with a body surface area more than 1 meter-squared

4 mg PO 3 times daily.[52194] Give the first dose 30 minutes prior to chemotherapy or 1 to 2 hours prior to radiation.[40241] May be continued for 1 to 5 days after completion of therapy.[40241] [52191]

Infants† and Children less than 4 years† with a body surface area 0.6 to 1 meter-squared

3 mg PO 3 times daily.[52194] Give the first dose 30 minutes prior to chemotherapy or 1 to 2 hours prior to radiation.[40241] May be continued for 1 to 5 days after completion of therapy.[40241] [52191]

Infants† and Children less than 4 years† with a body surface area 0.3 to 0.6 meter-squared

2 mg PO 3 times daily.[52192] [52194] Give the first dose 30 minutes prior to chemotherapy or 1 to 2 hours prior to radiation.[40241] May be continued for 1 to 5 days after completion of therapy.[40241] [52191]

Infants† and Children less than 4 years† with a body surface area less than 0.3 meter-squared

1 mg PO 3 times daily.[52194] Give the first dose 30 minutes prior to chemotherapy or 1 to 2 hours prior to radiation.[40241] May be continued for 1 to 5 days after completion of therapy.[40241] [52191]

For the treatment of post-operative nausea/vomiting (PONV)†

Intravenous dosage

Adults and Adolescents

4 mg IV once; a 5-HT3 antagonist is recommended if no prophylaxis was given, or for those who received a prophylactic antiemetic from another drug class. Administration of a second IV dose postoperatively in response to inadequate control is generally not effective; consider use of an antiemetic from another pharmacologic class.[57398]

Children weighing more than 40 kg

4 mg IV once; a 5-HT3 antagonist is recommended if no prophylaxis was given. Administration of a second IV dose postoperatively in response to inadequate control is generally not effective; consider use of an antiemetic from another pharmacologic class.[31266] [49437]

Infants and Children weighing 40 kg or less

0.05 to 0.1 mg/kg IV once; a 5-HT3 antagonist is recommended if no prophylaxis was given. Administration of a second IV dose postoperatively in response to inadequate control is generally not effective; consider use of an antiemetic from another pharmacologic class.[31266] [49437] Among children who had at least 2 postoperative episodes of retching or vomiting within 2 hours of surgery and who had not received prophylaxis, 53% had complete control of vomiting (no emesis and no rescue 24 hours after the dose) with a single 0.1 mg/kg (Max: 4 mg) IV ondansetron dose as compared with 17% of placebo recipients.[55979]

For post-operative nausea/vomiting (PONV) prophylaxis

Intravenous dosage

Adults, Adolescents, and Children weighing more than 40 kg

4 mg IV as single dose given immediately prior to or following anesthesia induction, or once postoperatively if patient experiences nausea/vomiting shortly after surgery. Administration of a second IV dose postoperatively in response to inadequate control is generally not effective; use of an antiemetic from another pharmacologic class should be considered.[31266] [57398]

Infants and Children weighing 40 kg or less

0.05 to 0.1 mg/kg IV as single dose given immediately prior to or following anesthesia induction, or once postoperatively if patient experiences nausea/vomiting shortly after surgery. Max: 4 mg/dose. Administration of a second IV dose postoperatively in response to inadequate control is generally not effective; use of an antiemetic from another pharmacologic class should be considered.[31266] [49437] [52205]

Intramuscular dosage

Adults and Adolescents

4 mg IM as single dose given immediately before anesthesia induction, or once postoperatively if patient experiences nausea/vomiting shortly after surgery. Administration of a second dose postoperatively in response to inadequate control is generally not effective; use of an antiemetic from another pharmacologic class should be considered.[31266]

Oral dosage

Adults

16 mg PO as single dose given 1 hour before anesthesia induction.[49444] Alteratively, 8 mg ODT PO as a single dose given at the end of surgery is as effective as 4 mg IV according to clinical practice guidelines.[57398]

Infants†, Children†, and Adolescents†

0.15 mg/kg PO as single dose, immediately prior to or after anesthesia induction, or once postoperatively if patient experiences nausea/vomiting shortly after surgery. Max: 8 mg/dose.[52220] Administration of a second dose postoperatively in response to inadequate control is generally not effective; use of an antiemetic from another pharmacologic class should be considered.[31266] [49437]

For the treatment of pregnancy-induced nausea/vomiting†

Oral dosage

Adult pregnant females

4 mg PO every 8 hours. Oral ondansetron is a third-line pharmacologic option if the patient is still experiencing persistent symptoms and is not dehydrated after a trial of nonpharmacologic options and other pharmacologic options (e.g., vitamin B6, doxylamine, promethazine, prochlorperzine, dimenhydrinate, diphenhydramine).[66066]

Intravenous dosage

Adult pregnant females

8 mg IV over 15 minutes every 12 hours. IV ondansetron is a third-line pharmacologic option if the patient is still experiencing persistent symptoms and is dehydrated after a trial of nonpharmacologic options and other pharmacologic options (e.g., vitamin B6, doxylamine, promethazine, prochlorperzine, dimenhydrinate, diphenhydramine).[66066]

For the short-term treatment of nausea/vomiting associated with acute gastroenteritis†

Intravenous dosage

Infants, Children, and Adolescents

0.15 mg/kg/dose (Max: 8 mg/dose) IV as a single dose has been used along with oral or IV rehydration.[27475] [57888] Although routine use of antiemetics is not recommended, some studies have shown that single IV doses of ondansetron are safe and effective for reducing vomiting and increasing patients' ability to tolerate oral rehydration.[27475] [52201] [52241] [57888]

Oral dosage

Children and Adolescents weighing more than 30 kg

6 to 8 mg PO as a single dose along with oral or IV rehydration.[52245] [44904] Alternatively, 0.2 mg/kg/dose PO every 8 hours for 3 doses has also been studied.[57896] Although routine use of antiemetics is not recommended for acute gastroenteritis, some studies have found that single and multiple oral doses of ondansetron are safe and effective for reducing vomiting and increasing patients' ability to tolerate oral rehydration.[52201] [52241] [52245] [57896]

Children weighing 15 to 30 kg

4 mg PO as a single dose along with oral or IV rehydration.[52245] [44904] Alternatively, 0.2 mg/kg/dose PO every 8 hours for 3 doses has also been studied.[57896] Although routine use of antiemetics is not recommended for acute gastroenteritis in guidelines, some studies have found that single and multiple oral doses of ondansetron are safe and effective for reducing vomiting and increasing patients' ability to tolerate oral rehydration.[52201] [52241] [52245] [57896]

Infants and Children 6 months and older weighing 8 to 15 kg

2 mg PO as a single dose along with oral or IV rehydration.[52245] [44904] Alternatively, 0.2 mg/kg/dose PO every 8 hours for 3 doses has also been studied.[57896] Although routine use of antiemetics is not recommended for acute gastroenteritis, studies have shown that single and multiple oral doses of ondansetron are safe and effective for reducing vomiting and increasing patients' ability to tolerate oral rehydration.[52201] [52241] [52245] [57896]

For the treatment of pruritus† secondary to cholestasis

Intravenous and Oral dosage

Adults

Five patients with severe pruritus secondary to cholestasis were treated with ondansetron. An initial dose of 8 mg IV was administered. Pruritus was relieved completely in 3 patients and partially in 2 with effects lasting 5—16 hours. Three patients were continued on oral therapy of 8 mg PO twice daily, with decreased severity of symptoms.[24001] Dosage should be adjusted in hepatic impairment.

For the maintenance treatment of alcohol dependence†

Oral dosage

Adults

A dosage of 4 mcg/kg PO twice per day, combined with weekly standardized group behavioral therapy, was effective in reducing alcohol consumption. Ondansetron was superior to placebo in increasing percentage of days abstinent and total days abstinent per study week. The results suggest that ondansetron is an effective treatment for patients with early-onset ethanol dependence, presumably by ameliorating an underlying serotonergic abnormality.[26327] NOTE: Pharmacotherapy should be used as a part of a comprehensive management program that includes psychosocial support and treatment.

For the treatment of cyclic vomiting syndrome†

Intravenous dosage

Adults

8 mg IV every 4 to 6 hours as needed.[68523]

Children and Adolescents 2 to 17 years

0.3 to 0.4 mg/kg/dose (Max: 20 mg/dose) IV every 4 to 6 hours as needed.[31266] [52129] [68524]

Oral dosage (disintegrating tablet)

Adults

8 mg PO every 6 to 8 hours as needed for 24 to 48 hours if intravenous therapy is initially effective.[68523]

For the treatment of nausea/vomiting† in the emergency department or prehospital

Intravenous or Intramuscular dosage

Adults

4 mg IV or IM as a single dose.[44224] [68519] [68555] [68572] [68573]

Children and Adolescents 4 to 17 years

4 mg IV or IM as a single dose.[68573]

Oral dosage

Adults

4 mg PO as a single dose.[68573] [68555]

Children and Adolescents 4 to 17 years

4 mg PO as a single dose.[68573]

Therapeutic Drug Monitoring

Maximum Dosage Limits

  • Adults

    24 mg/day PO; 0.45 mg/kg/day IV (in 3 divided doses, max single dose = 16 mg IV).

  • Geriatric

    24 mg/day PO; 0.45 mg/kg/day IV (in 3 divided doses, max single dose = 16 mg IV).

  • Adolescents

    0.15 mg/kg/dose IV (Max: 16 mg/dose IV). 16 mg/day PO.

  • Children

    < 4 years: 0.15 mg/kg/dose IV (Max: 16 mg/dose). Safety and efficacy have not been established for PO formulation.

    4—11 years: 0.15 mg/kg/dose IV (Max: 16 mg/dose). 12 mg/day PO.

    >= 12 years: 0.15 mg/kg/dose IV (Max: 16 mg/dose). 16 mg/day PO.

  • Infants

    1—5 months: 0.1 mg/kg IV (single dose). Safety and efficacy have not been established for PO formulation.

    >= 6 months: 0.15 mg/kg/dose IV (Max: 16 mg/dose IV). Safety and efficacy have not been established for PO formulation.

  • Neonates

    Safety and efficacy have not been established.

Patients with Hepatic Impairment Dosing

Per the manufacturer, ondansetron dosage should not exceed 8 mg/day IV or PO in adult patients with severe hepatic impairment (Child-Pugh score >= 10). In such patients, plasma clearance is reduced, resulting in a dramatically prolonged elimination half-life.[31266] No specific pediatric recommendations are available.

Patients with Renal Impairment Dosing

No dosage adjustments are recommended. A small percentage (5%) of ondansetron is renally cleared. In patients with severe renal impairment (CrCl < 30 ml/min) the mean plasma clearance is reduced; however, the reduction is not consistent with an increase in half-life.[31266]

† Off-label indication
Revision Date: 02/05/2023, 03:55:17 PM

References

24001 - Raderer M, Muller C, Scheithauer W. Ondansetron for pruritus due to cholestasis. N Engl J Med 1994;330:1540.26327 - Johnson BA, Roache JD, Javors MA. Ondansetron for reduction of drinking among biologically predisposed alcoholic patients, a randomized controlled trial. JAMA 2000;284:963-971.27475 - Reeves JJ, Shannon MW, Fleisher GR. Ondansetron decreases vomiting associated with acute gastroenteritis: A randomized, controlled trial. Pediatrics 2002;109:1-6.31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.40241 - Zofran (ondansetron) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.44224 - Barrett TW, DiPersio DM, Jenkins CA, et al. A randomized, placebo-controlled trial of ondansetron, metoclopramide, and promethazine in adults. Am J Emerg Med 2011;29:247-55.44904 - Roslund G, Hepps TS, Mc Quillen KK. The role of oral ondansetron in children with vomiting as a result of acute gastritis/gastroenteritis who have failed oral rehydration therapy: a randomized controlled trial. Ann Emerg Med. 2008;52:22-949435 - Dupuis LL, Sung L, Molassiotis A, et al. 2016 updated MASCC/ESMO consensus recommendations: Prevention of acute chemotherapy-induced nausea and vomiting in children. Support Care Cancer 2017;25:323–331.49437 - Gan TJ, Meyer TA, Apfel CC, et al. Society for Ambulatory Anesthesia guidelines for the management of postoperative nausea and vomiting. Anesth Analg 2007;105(6):1615-1628.49444 - Ondansetron hydrochloride (Zofran) tablets and oral solution package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.51100 - FDA Drug Safety Communication: Ondansetron (Zofran) IV-QT prolongation. Retrieved June 29, 2012. Available on the World Wide Web at: http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm310219.htm?source=govdelivery.52129 - Li UK, Lefevre F, Chelimsky GG. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrtion consensus statement on the diagnosis and and management of cyclic vomiting syndrome. J Pediatr Gastroenterol Nutr 2008;47:379-393.52188 - Sandoval C, Corbi D, Strobino B. Randomized double-blind comparison of single high-dose ondansetron and multiple standard-dose ondansetron in chemotherapy-naive pediatric oncology patients. Cancer Invest 1999;17:309-313.52191 - Jurgens H, McQuade B. Ondansetron as prophylaxis for chemotherapy and radiotherapy-induced emesis in children. Oncology 1992;49:279-285.52192 - Hewitt M, McQuade B, Stevens R. The efficacy and safety of ondansetron in the prophylaxis of cancer-chemotherapy induced nausea and vomiting in children. Clin Oncol (R Coll Radiol) 1993;5:11-14.52194 - Pinkerton CR, Williams D, Wootton C. 5-HT3 antagonist ondansetron an effective outpatient antiemetic in cancer treatment. Arch Dis Child 1990;65:822-825.52201 - American Academy of Pediatrics Provisional Committee on Quality Improvement, Subcommittee on Acute Gastroenteritis. Practice parameter: the management of acute gastroenteritis in young children. Pediatrics 1996;97:424-435.52202 - American Society of Hospital Pharmacists (ASHP). ASHP therapeutic guidelines on the pharmacologic management of nausea and vomiting in adult and pediatric patients receiving chemotherapy or radiation therapy or undergoing surgery. Am J Health-Syst Pharm 1999;56:729-764.52205 - Gan TJ, Meyer T, Apfel CC. Consensus guidelines for managing postoperative nausea and vomiting. Anesth Analg 2003;97:62-71.52220 - Rose JB, Brenn BR, Corddry DH. Preoperative oral ondansetron for pediatric toncilletomy. Anesth Analg 1996;82:558-562.52241 - King CK, Glass R, Bresee JS, Duggan C. Centers for Disease Control and Prevention (CDC). Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy. MMWR Recomm Rep 2003;52(RR-16):1-16.52245 - Freedman SB, Adler M, Seshadri R, et al. Oral ondansetron for gastroenteritis in a pediatric emergency department. N Engl J Med 2006;354:1698-1705.55979 - Khalil S, Rodarte A, Weldon BC, et al. Intravenous ondansetron in established postoperative emesis in children. Anesthesiology 1996;85(2):270-6.57398 - Gan TJ, Diemunsch P, Habib AS, et al. Consensus guidelines for the management of postoperative nausea and vomiting. Anesth Analg 2014;118:85-113.57888 - Stork CM, Brown KM, Reilly TH, et al. Emergency department treatment of viral gastritis using intravenous ondansetron or dexamethasone in children. Acad Emerg Med 2006;13:1027-33.57896 - Yilmaz HL, Yildizdas RD, Sertdemir Y. Clinical trial:oral ondansetron for reducing vomiting secondary to acute gastroenteritis in children-a double-blind randomized study. Aliment Pharmacol Ther 2010;31:82-91.63197 - Hesketh PJ, Kris MG, Basch E, et al. Antiemetics: American Society of Clinical Oncology clinical practice guideline update. J Clin Oncol 2017;35:3240-61.66066 - American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin Number 189: Nausea and vomiting of pregnancy. Obstet Gynecol 2018;131:15-30. Reaffirmed 2019.68519 - Patanwala AE, Amini R, Hays DP, et al. Antiemetic therapy for nausea and vomiting in the emergency department. J Emerg Med. 2010 Sep;39:330-6.68523 - Venkatesan T, Levinthal DJ, Tarbell SE, et al. Guidelines on management of cyclic vomiting syndrome in adults by the American Neurogastroenterology and Motility Society and the Cyclic Vomiting Syndrome Association. Neurogastroenterol Motil. 2019 Jun;31 Suppl 2:e13604.68524 - Li BUK. Managing cyclic vomiting syndrome in children: beyond the guidelines. Eur J Pediatr. 2018 Oct;177:1435-1442.68555 - Natesan S, Lee J, Volkamer H, et al. Evidence-Based Medicine Approach to Abdominal Pain. Emerg Med Clin North Am. 2016 May;34:165-90.68572 - Egerton-Warburton D, Meek R, Mee MJ, et al. Antiemetic use for nausea and vomiting in adult emergency department patients: randomized controlled trial comparing ondansetron, metoclopramide, and placebo. Ann Emerg Med. 2014 Nov;64:526-532.e1.68573 - Salvucci AA, Squire B, Burdick M, et al. Ondansetron is safe and effective for prehospital treatment of nausea and vomiting by paramedics. Prehosp Emerg Care. 2011 Jan-Mar;15:34-8.

How Supplied

Dextrose, Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 32mg/50ml in Dextrose 5% Solution for Injection (55390-0234) (Bedford Laboratories, a Hikma Company) (off market)

Dextrose, Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 32mg/50ml in Dextrose 5% Solution for Injection (00409-4760) (Hospira Worldwide, Inc., a Pfizer Company) (off market)

Dextrose, Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 32mg/50ml in Dextrose 5% Solution for Injection (00069-0700) (Pfizer Injectables) (off market)

Dextrose, Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 32mg/50ml in Dextrose 5% Solution for Injection (00703-7239) (Teva Pharmaceuticals USA) (off market)

Dextrose, Ondansetron Hydrochloride Solution for injection

Zofran 32mg/50ml in Dextrose 5% Solution for Injection (00173-0461) (GlaxoSmithKline Group of Companies) (off market)

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (60687-0252) (American Health Packaging) null

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (65162-0691) (Amneal Pharmaceuticals LLC) nullOndansetron Hydrochloride 4mg/5mL Solution package photo

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (60505-0381) (Apotex Corp) (off market)

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (62135-0555) (Chartwell Pharmaceuticals) null

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (00054-0064) (Hikma Pharmaceuticals USA Inc.) nullOndansetron Hydrochloride 4mg/5mL Solution package photo

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (00904-7073) (Major Pharmaceuticals Inc, a Harvard Drug Group Company) null

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (16714-6710) (NorthStar Rx LLC) (off market)Ondansetron Hydrochloride 4mg/5mL Solution package photo

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (16714-0671) (NorthStar Rx LLC) null

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (68094-0325) (Precision Dose, Inc.) null

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (68094-0763) (Precision Dose, Inc.) null

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (54838-0555) (Silarx Pharmaceuticals Inc) nullOndansetron Hydrochloride 4mg/5mL Solution package photo

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (51672-4091) (Taro Pharmaceuticals USA Inc) nullOndansetron Hydrochloride 4mg/5mL Solution package photo

Ondansetron Hydrochloride Oral solution

Ondansetron Hydrochloride 4mg/5mL Solution (50111-0819) (Teva Pharmacueticals USA) (off market)Ondansetron Hydrochloride 4mg/5mL Solution package photo

Ondansetron Hydrochloride Oral solution

Zofran 4mg/5mL Solution (00173-0489) (GlaxoSmithKline Group of Companies) (off market)Zofran 4mg/5mL Solution package photo

Ondansetron Hydrochloride Oral solution

Zofran 4mg/5mL Solution (00173-0489) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (68084-0220) (American Health Packaging) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (60687-0636) (American Health Packaging) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (60505-1311) (Apotex Corp) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (67877-0169) (Ascend Laboratories, LLC a Subsidiary of Alkem Laboratories Ltd) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (65862-0187) (Aurobindo Pharma USA Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (50268-0621) (AvPAK; a Division of AvKARE Inc) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (62135-0350) (Chartwell Pharmaceuticals) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (57237-0075) (Citron Pharma LLC) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (69339-0171) (Dash Pharmaceuticals LLC) nullOndansetron Hydrochloride 4mg Tablet package photo

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (55111-0153) (Dr. Reddy's Laboratories, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (71930-0017) (Eywa Pharma Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (68462-0105) (Glenmark Pharmaceuticals) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (59762-2990) (Greenstone Ltd) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (00143-2422) (Hikma Pharmaceuticals USA Inc.) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (00904-6208) (Major Pharmaceuticals Inc, a Harvard Drug Group Company) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (00904-6551) (Major Pharmaceuticals Inc, a Harvard Drug Group Company) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (51079-0524) (Mylan Institutional LLC ) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (00378-0315) (Mylan Pharmaceuticals Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (16714-0159) (NorthStar Rx LLC) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (43063-0746) (PD-Rx Pharmaceuticals, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (72789-0034) (PD-Rx Pharmaceuticals, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (45802-0127) (Perrigo Pharmaceuticals Company) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (00781-5257) (Sandoz Inc. a Novartis Company) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (00781-1679) (Sandoz Inc. a Novartis Company) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (62756-0130) (Sun Pharmaceutical Industries, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (63304-0458) (Sun Pharmaceutical Industries, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (00093-0233) (Teva Pharmaceuticals USA) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (52152-0538) (Teva/Actavis US) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 4mg Tablet (45963-0538) (Teva/Actavis US) null

Ondansetron Hydrochloride Oral tablet

Zofran 4mg Tablet (00173-0446) (GlaxoSmithKline Group of Companies) (off market)

Ondansetron Hydrochloride Oral tablet

Zofran 4mg Tablet (00173-0446) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Hydrochloride Oral tablet

Zofran 4mg Tablet (00078-0675) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (68084-0221) (American Health Packaging) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (60687-0647) (American Health Packaging) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (60505-1312) (Apotex Corp) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (67877-0170) (Ascend Laboratories, LLC a Subsidiary of Alkem Laboratories Ltd) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (65862-0188) (Aurobindo Pharma USA Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (50268-0622) (AvPAK; a Division of AvKARE Inc) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (10544-0575) (Blenheim Pharmacal, Inc.) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (62135-0351) (Chartwell Pharmaceuticals) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (57237-0076) (Citron Pharma LLC) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (69339-0172) (Dash Pharmaceuticals LLC) nullOndansetron Hydrochloride 8mg Tablet package photo

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (55111-0154) (Dr. Reddy's Laboratories, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (71930-0018) (Eywa Pharma Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (68462-0106) (Glenmark Pharmaceuticals) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (59762-2993) (Greenstone Ltd) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (00143-2423) (Hikma Pharmaceuticals USA Inc.) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (00904-6209) (Major Pharmaceuticals Inc, a Harvard Drug Group Company) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (00904-6552) (Major Pharmaceuticals Inc, a Harvard Drug Group Company) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (63739-0333) (McKesson Packaging) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (51079-0525) (Mylan Institutional LLC ) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (00378-0344) (Mylan Pharmaceuticals Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (16714-0160) (NorthStar Rx LLC) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (43063-0792) (PD-Rx Pharmaceuticals, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (43063-0770) (PD-Rx Pharmaceuticals, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (45802-0205) (Perrigo Pharmaceuticals Company) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (00781-5258) (Sandoz Inc. a Novartis Company) nullOndansetron Hydrochloride 8mg Tablet package photo

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (00781-1681) (Sandoz Inc. a Novartis Company) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (63304-0459) (Sun Pharmaceutical Industries, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (62756-0131) (Sun Pharmaceutical Industries, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (00093-7236) (Teva Pharmaceuticals USA) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (45963-0539) (Teva/Actavis US) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 8mg Tablet (52152-0539) (Teva/Actavis US) (off market)

Ondansetron Hydrochloride Oral tablet

Zofran 8mg Tablet (00173-0447) (GlaxoSmithKline Group of Companies) (off market)

Ondansetron Hydrochloride Oral tablet

Zofran 8mg Tablet (00173-0447) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Hydrochloride Oral tablet

Zofran 8mg Tablet (00078-0676) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 24mg Tablet (55111-0156) (Dr. Reddy's Laboratories, Inc.) null

Ondansetron Hydrochloride Oral tablet

Ondansetron Hydrochloride 24mg Tablet (00143-2424) (Hikma Pharmaceuticals USA Inc.) null

Ondansetron Hydrochloride Oral tablet

Zofran 24mg Tablet (00173-0680) (GlaxoSmithKline Group of Companies) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (23360-0016) (Akorn-Strides LLC) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (23360-0016) (Akorn-Strides LLC) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (60505-0744) (Apotex Corp) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (60505-0744) (Apotex Corp) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (10019-0905) (Baxter Anesthesia/Critical Care) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (10019-0906) (Baxter Anesthesia/Critical Care Oncology) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (55390-0121) (Bedford Laboratories, a Hikma Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (55390-0121) (Bedford Laboratories, a Hikma Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (63323-0373) (Fresenius Kabi AG) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (63323-0374) (Fresenius Kabi AG) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00641-6078) (Hikma Pharmaceuticals USA inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00143-9891) (Hikma Pharmaceuticals USA Inc.) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (61703-0244) (Hospira Worldwide, Inc., a Pfizer Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00409-1120) (Hospira Worldwide, Inc., a Pfizer Company) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00409-4759) (Hospira Worldwide, Inc., a Pfizer Company) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (61703-0245) (Hospira Worldwide, Inc., a Pfizer Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00781-3057) (Sandoz Inc. a Novartis Company) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00781-3057) (Sandoz Inc. a Novartis Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00781-3010) (Sandoz Inc. a Novartis Company) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (62756-0181) (Sun Pharmaceutical Industries, Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (62756-0182) (Sun Pharmaceutical Industries, Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00703-7221) (Teva Pharmaceuticals USA) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (00703-7221) (Teva Pharmaceuticals USA) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (64679-0726) (Wockhardt USA, LLC) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (64679-0727) (Wockhardt USA, LLC) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (Amerinet) (00409-4755) (Hospira Worldwide, Inc., a Pfizer Company) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (NOVAPLUS) (10019-0906) (Baxter Anesthesia/Critical Care Oncology) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (NOVAPLUS) (55390-0307) (Bedford Laboratories, a Hikma Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (NOVAPLUS) (55390-0307) (Bedford Laboratories, a Hikma Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (NOVAPLUS) (00641-6080) (Hikma Pharmaceuticals USA inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 2mg/ml Solution for Injection (NOVAPLUS) (10019-0906) (Hikma Pharmaceuticals USA inc.) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20ml Solution for Injection (10019-0906) (Hikma Pharmaceuticals USA inc.) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20ml Solution for Injection (00641-6079) (Hikma Pharmaceuticals USA Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20ml Solution for Injection (67457-0441) (Mylan Institutional LLC ) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20ml Solution for Injection (00069-1340) (Mylan Institutional LLC ) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20ml Solution for Injection (00069-1340) (Pfizer Injectables) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20ml Solution for Injection (00703-7226) (Teva Pharmaceuticals USA) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20ml Solution for Injection (00703-7226) (Teva Pharmaceuticals USA) (off market)Ondansetron Hydrochloride 40mg/20ml Solution for Injection package photo

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (16729-0298) (Accord Healthcare, Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (70860-0777) (Athenex Pharmaceutical Division LLC) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (23155-0549) (Avet Pharmaceuticals Inc.) nullOndansetron Hydrochloride 40mg/20mL Solution for Injection package photo

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (23155-0168) (Avet Pharmaceuticals Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (36000-0013) (Baxter Healthcare Corporation) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (55150-0126) (Eugia US LLC fka AuroMedics Pharma LLC) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (72266-0124) (Fosun Pharma USA Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (00143-9890) (Hikma Pharmaceuticals USA inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (25021-0782) (Sagent Pharmaceuticals) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (PREMIER ProRx) (23155-0377) (Avet Pharmaceuticals Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 40mg/20mL Solution for Injection (PREMIER ProRx) (23155-0550) (Avet Pharmaceuticals Inc.) nullOndansetron Hydrochloride 40mg/20mL Solution for Injection (PREMIER ProRx) package photo

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (23155-0196) (Avet Pharmaceuticals Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (36000-0012) (Baxter Healthcare Corporation) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (55150-0125) (Eugia US LLC fka AuroMedics Pharma LLC) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (10019-0905) (Hikma Pharmaceuticals USA inc.) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (00143-9891) (Hikma Pharmaceuticals USA inc.) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (00409-1120) (Hospira Worldwide, Inc., a Pfizer Company) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (00409-4755) (Hospira Worldwide, Inc., a Pfizer Company) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (67457-0440) (Mylan Institutional LLC ) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (00069-1340) (Mylan Institutional LLC ) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (00069-1340) (Pfizer Injectables) (off market)

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (16729-0297) (Accord Healthcare, Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (60505-6130) (Apotex Corp) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (70860-0776) (Athenex Pharmaceutical Division LLC) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (23155-0547) (Avet Pharmaceuticals Inc.) nullOndansetron Hydrochloride 4mg/2mL Solution for Injection package photo

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (72572-0520) (Civica, Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (72266-0123) (Fosun Pharma USA Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (25021-0777) (Sagent Pharmaceuticals) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2ml Solution for Injection (PREMIER ProRx) (23155-0378) (Avet Pharmaceuticals Inc.) null

Ondansetron Hydrochloride Solution for injection

Ondansetron Hydrochloride 4mg/2mL Solution for Injection (PREMIER ProRx) (23155-0548) (Avet Pharmaceuticals Inc.) nullOndansetron Hydrochloride 4mg/2mL Solution for Injection (PREMIER ProRx) package photo

Ondansetron Hydrochloride Solution for injection

Simplist Ondansetron Hydrochloride 4mg/2ml Prefilled Syringe Solution for Injection (76045-0103) (BD Rx Inc., a Fresenius Kabi USA Company) nullSimplist Ondansetron Hydrochloride 4mg/2ml Prefilled Syringe Solution for Injection package photo

Ondansetron Hydrochloride Solution for injection

Zofran 2mg/ml Solution for Injection (00173-0442) (GlaxoSmithKline Group of Companies) (off market)Zofran 2mg/ml Solution for Injection package photo

Ondansetron Hydrochloride Solution for injection

Zofran 2mg/ml Solution for Injection (00173-0442) (GlaxoSmithKline Group of Companies) (off market)Zofran 2mg/ml Solution for Injection package photo

Ondansetron Hydrochloride Solution for injection

Zofran 2mg/ml Solution for Injection (00173-0442) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Hydrochloride, Sodium Chloride Solution for injection

Ondansetron Hydrochloride 32mg/50ml in Sodium Chloride 0.9% Solution for Injection (00338-1762) (Baxter Medication Delivery) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (65862-0390) (Aurobindo Pharma USA Inc.) null

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (68001-0246) (BluePoint Laboratories) nullOndansetron 4mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (62135-0121) (Chartwell Pharmaceuticals) null

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (57237-0077) (Citron Pharma LLC) null

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (58177-0363) (Ethex Corporation) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (68462-0157) (Glenmark Pharmaceuticals) nullOndansetron 4mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (00378-7732) (Mylan Pharmaceuticals Inc.) null

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (16714-0200) (NorthStar Rx LLC) null

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (43063-0560) (PD-Rx Pharmaceuticals, Inc.) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (43063-0052) (PD-Rx Pharmaceuticals, Inc.) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (55289-0559) (PD-Rx Pharmaceuticals, Inc.) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (55289-0559) (PD-Rx Pharmaceuticals, Inc.) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (43063-0857) (PD-Rx Pharmaceuticals, Inc.) null

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (33358-0498) (RxChange Co.) null

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (00781-5265) (Sandoz Inc. a Novartis Company) nullOndansetron 4mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (00781-5238) (Sandoz Inc. a Novartis Company) nullOndansetron 4mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (62756-0240) (Sun Pharmaceutical Industries, Inc.) nullOndansetron 4mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (00093-7301) (Teva Pharmaceuticals USA) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 4mg Orally Disintegrating Tablet (50111-0945) (Teva Pharmacueticals USA) null

Ondansetron Oral disintegrating tablet

Zofran ODT 4mg Orally Disintegrating Tablet (00173-0569) (GlaxoSmithKline Group of Companies) (off market)Zofran ODT 4mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Zofran ODT 4mg Orally Disintegrating Tablet (00173-0569) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Oral disintegrating tablet

Zofran ODT 4mg Orally Disintegrating Tablet (00078-0679) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (65862-0391) (Aurobindo Pharma USA Inc.) nullOndansetron 8mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (68001-0247) (BluePoint Laboratories) nullOndansetron 8mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (62135-0122) (Chartwell Pharmaceuticals) null

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (57237-0078) (Citron Pharma LLC) null

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (58177-0364) (Ethex Corporation) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (68462-0158) (Glenmark Pharmaceuticals) nullOndansetron 8mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (00378-7734) (Mylan Pharmaceuticals Inc.) null

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (16714-0201) (NorthStar Rx LLC) null

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (43063-0592) (PD-Rx Pharmaceuticals, Inc.) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (43063-0273) (PD-Rx Pharmaceuticals, Inc.) null

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (43063-0870) (PD-Rx Pharmaceuticals, Inc.) null

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (33358-0512) (RxChange Co.) null

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (00781-5239) (Sandoz Inc. a Novartis Company) nullOndansetron 8mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (00781-5266) (Sandoz Inc. a Novartis Company) nullOndansetron 8mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (62756-0356) (Sun Pharmaceutical Industries, Inc.) nullOndansetron 8mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (00093-7302) (Teva Pharmaceuticals USA) (off market)

Ondansetron Oral disintegrating tablet

Ondansetron 8mg Orally Disintegrating Tablet (50111-0946) (Teva Pharmacueticals USA) null

Ondansetron Oral disintegrating tablet

Zofran ODT 8mg Orally Disintegrating Tablet (00173-0570) (GlaxoSmithKline Group of Companies) (off market)Zofran ODT 8mg Orally Disintegrating Tablet package photo

Ondansetron Oral disintegrating tablet

Zofran ODT 8mg Orally Disintegrating Tablet (00078-0680) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Oral disintegrating tablet

Zofran ODT 8mg Orally Disintegrating Tablet (00173-0570) (Novartis Pharmaceuticals Corporation) (off market)

Ondansetron Oral Dissolving film

Zuplenz 4mg Oral Soluble Film (57881-0444) (Galena Biopharma) (off market)

Ondansetron Oral Dissolving film

Zuplenz 4mg Oral Soluble Film (57881-0444) (Midatech Pharma US formerly DARA BioSciences, Inc.) (off market)

Ondansetron Oral Dissolving film

Zuplenz 4mg Oral Soluble Film (89141-0444) (Midatech Pharma US formerly DARA BioSciences, Inc.) null

Ondansetron Oral Dissolving film

Zuplenz 4mg Oral Soluble Film (49884-0324) (Par Pharmaceuticals, an Endo Company) (off market)

Ondansetron Oral Dissolving film

Zuplenz 4mg Oral Soluble Film (43288-0104) (Praelia Pharmaceuticals ) (off market)

Ondansetron Oral Dissolving film

Zuplenz 8mg Oral Soluble Film (57881-0448) (Galena Biopharma) (off market)

Ondansetron Oral Dissolving film

Zuplenz 8mg Oral Soluble Film (57881-0448) (Midatech Pharma US formerly DARA BioSciences, Inc.) (off market)

Ondansetron Oral Dissolving film

Zuplenz 8mg Oral Soluble Film (89141-0448) (Midatech Pharma US formerly DARA BioSciences, Inc.) null

Ondansetron Oral Dissolving film

Zuplenz 8mg Oral Soluble Film (49884-0325) (Par Pharmaceuticals, an Endo Company) (off market)

Ondansetron Oral Dissolving film

Zuplenz 8mg Oral Soluble Film (43288-0108) (Praelia Pharmaceuticals ) (off market)

Description/Classification

Description

Ondansetron is an oral and parenteral serotonin (5-HT3) receptor antagonist. Ondansetron is used as an antiemetic agent for the prevention and treatment of nausea and vomiting during chemotherapy, radiation therapy, and surgery.[31266] Ondansetron has occasionally been utilized for the treatment of hyperemesis gravidarum refractory to other treatments. Novel investigational uses of ondansetron include treatment of gastrointestinal motility disorders and drug dependence (e.g., alcoholism). In the pediatric population, ondansetron is also used off-label for cyclic vomiting syndrome and gastroenteritis-induced vomiting.[52241][52129] Ondansetron is an extremely safe and highly effective antiemetic compared to older, traditional antiemetics (e.g., metoclopramide, droperidol); however, there is a risk of dose-dependent QT-prolongation and torsade de points.[31266][52167] When administered at optimal doses, ondansetron and other 5HT3 receptor antagonists (e.g., granisetron) are equally effective.[52202] The American Society of Clinical Oncology (ASCO) guidelines recommend that adult patients who are treated with moderate to high-emetic-risk chemotherapy agents should be offered a 3-drug combination of a 5-HT3 receptor antagonist, a neurokinin 1 (NK1) receptor antagonist, and dexamethasone; olanzapine is also added to the 3-drug combination during use of high-emetic-risk agents.[63197] Children receiving moderate to high-emetic-risk agents should be offered a 2-drug combination of a 5-HT3 receptor antagonist and dexamethasone; aprepitant is also added to the 2-drug combination during use of high-emetic-risk agents.[63197][49435] The Society for Ambulatory Anesthesia (SAMBA) guidelines recommend the use of a 5-HT3 receptor antagonist as the first choice for prophylaxis of postoperative nausea and vomiting in children.[49437]

Classifications

  • Alimentary Tract and Metabolism
    • Antiemetics and Antinauseants
      • Serotonin/5HT3 Antagonist Antiemetics/antinauseants
Revision Date: 09/21/2020, 02:04:11 PM

References

31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.49435 - Dupuis LL, Sung L, Molassiotis A, et al. 2016 updated MASCC/ESMO consensus recommendations: Prevention of acute chemotherapy-induced nausea and vomiting in children. Support Care Cancer 2017;25:323–331.49437 - Gan TJ, Meyer TA, Apfel CC, et al. Society for Ambulatory Anesthesia guidelines for the management of postoperative nausea and vomiting. Anesth Analg 2007;105(6):1615-1628.52129 - Li UK, Lefevre F, Chelimsky GG. North American Society for Pediatric Gastroenterology, Hepatology, and Nutrtion consensus statement on the diagnosis and and management of cyclic vomiting syndrome. J Pediatr Gastroenterol Nutr 2008;47:379-393.52167 - Culy CR, Bhana N, Plosker GL. Ondansetron: a review of its use as an antiemetic in children. Paediatr Drug 2001;3:441-479.52202 - American Society of Hospital Pharmacists (ASHP). ASHP therapeutic guidelines on the pharmacologic management of nausea and vomiting in adult and pediatric patients receiving chemotherapy or radiation therapy or undergoing surgery. Am J Health-Syst Pharm 1999;56:729-764.52241 - King CK, Glass R, Bresee JS, Duggan C. Centers for Disease Control and Prevention (CDC). Managing acute gastroenteritis among children: oral rehydration, maintenance, and nutritional therapy. MMWR Recomm Rep 2003;52(RR-16):1-16.63197 - Hesketh PJ, Kris MG, Basch E, et al. Antiemetics: American Society of Clinical Oncology clinical practice guideline update. J Clin Oncol 2017;35:3240-61.

Administration Information

General Administration Information

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

Route-Specific Administration

Oral Administration

  • All oral dosage forms are considered interchangeable.
  • All oral dosage forms may be administered without regard to meals.
  • Antacids do not interfere with ondansetron absorption.[49444]

Oral Solid Formulations

Oral disintegrating tablets (ODT):

  • DO NOT attempt to push ODT tablets through foil backing. With dry hands, peel back the foil of 1 blister and remove the tablet.
  • Place tablet on the tongue; it will dissolve in seconds. Once dissolved, the patient may swallow with saliva. Administration with liquid is not necessary.
  • Wash hands after administration.[49444]

Oral Liquid Formulations

  • Oral solution: Measure dose with a calibrated oral syringe or other calibrated container.

Other Oral Formulations

Oral soluble film (Zuplenz):

  • With dry hands, fold the pouch along the dotted line to expose the tear notch. While still folded, tear the pouch carefully along the edge and remove the oral soluble film just prior to dosing.
  • Place the film on the tongue; it will dissolve in 4 to 20 seconds. Once dissolved, the patient may swallow with saliva. Administration with liquid is not necessary.
  • When administering oral soluble films successively to reach a desired dose (i.e., 16 mg given as two 8 mg films) allow each film to dissolve completely before administering the next one.[41272]

Injectable Administration

  • Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.

Intravenous Administration

IV Push

  • Doses up to 4 mg may be administered undiluted (2 mg/mL) over at least 30 seconds and preferably over a period of 2 to 5 minutes.[31266]

 

Intermittent IV Infusion

  • For doses more than 4 mg and for chemotherapy-induced nausea and vomiting (CINV), dilute ondansetron in 50 mL of 5% Dextrose Injection or 0.9% Sodium Chloride Injection.
    • For patients 6 months to 1 year of age and/or 10 kg or less: Doses may be diluted in 10 to 50 mL of 5% Dextrose Injection or 0.9% Sodium Chloride Injection, depending on the fluid needs of the individual patient.
  • Infuse IV over 15 minutes.[31266]
  • Storage: Dilution is stable for 48 hours at room temperature.[31266][52214]

Intramuscular Administration

  • In adults, a 4 mg undiluted dose may be administered intramuscularly as a single injection.
  • Use aseptic technique. Inject deeply into a well-developed muscle mass. Aspirate prior to injection to avoid injection into a blood vessel.[31266]

Clinical Pharmaceutics Information

From Trissel's 2‚Ñ¢ Clinical Pharmaceutics Database

Ondansetron hydrochloride

pH Range
pH 3.3 to 4 (injection) pH 3 to 4 (premixed infusion)
ReferencesAnon. Manufacturer's information and labeling. (Package insert).
ReferencesZofran (ondansetron) injection package insert. East Hanover, NJ. Novartis Pharmaceuticals Corporation. 2021; Oct
Osmolality/Osmolarity
Ondansetron hydrochloride injection 2 mg/mL was found to be isotonic having a measured osmolality of 281 mOsm/kg. The ondansetron hydrochloride premixed infusion solution is also iso-osmotic having an osmolarity near 270 mOsm/L.
ReferencesAnon. Manufacturer's information and labeling. (Package insert).
ReferencesTrissel LA. Drug information- osmolalities. Data on file.
Stability
Ondansetron hydrochloride injection products in intact containers stored as directed by the manufacturers are stated to be stable until the labeled expiration date on the container. However, Tsui and Cave reported finding discolored ondansetron hydrochloride injection in intact vials of the drug. The lot of drug was within the expiration date period cited on the vial label. No explanation was found for the discoloration. Other vials of that lot remained colorless. Obviously, discolored ondansetron hydrochloride should be discarded. It was noted that this would have been much more difficult to observe if the solution had been prepackaged in syringes. Infusion Solutions Stability Reports: Leak and Woodford, Graham et al., and from Hagan et al. indicated that ondansetron hydrochloride is stable in common infusion solution such as dextrose 5% and sodium chloride 0.9% for longer periods ranging from 7 to 14 days at room temperature and 14 days to 30 days under refrigeration, depending on the length of the study. Stiles et al. reported that undiluted Glaxo ondansetron 2 mg/mL as hydrochloride and also diluted in sodium chloride 0.9% to a concentration of 0.24 mg/mL in CADD-1 polyvinyl chloride (PVC) plastic was stable. HPLC analysis found that the undiluted ondansetron hydrochloride underwent about 5% loss in 7 days at 30 degrees C. Ondansetron hydrochloride diluted in sodium chloride 0.9% exhibited no loss in 24 hours at 30 degrees C and in 30 days under refrigeration. Packaged in Syringes: Leak and Woodford reported that Glaxo ondansetron hydrochloride diluted in compatible infusion solutions is stable packaged in syringes composed of polypropylene and neoprene for 7 days at room temperature or refrigerated. Casto reported undiluted ondansetron 2 mg/mL as the hydrochloride and diluted to concentrations of 1, 0.5, and 0.25 mg/mL with dextrose 5% or with sodium chloride 0.9% packaged in polypropylene syringes was stable at room temperature for 48 hours, refrigerated for 14 days, and at -20 degrees C for 90 days. In addition, samples stored frozen at -20 degrees C for 90 days, followed by refrigerated storage for 14 days, followed by room temperature storage for 48 hours were also stable. HPLC analysis found most samples lost less than 5% during the respective study periods with none exceeding 10% loss. Paramedic Conditions: Gammon et al. reported on the stability of a number of drugs used by paramedics when exposed to the temperature range that is found in ambulances as documented by Brown et al. and Allegra et al. Undiluted ondansetron hydrochloride 2 mg/mL injection was stored at temperatures that cycled every 24 hours from -6 to 54 degrees C (2.12 to 129.2 degrees F) for 28 days. The drug was exposed to a total of 336 hours at each of the temperature extremes. The mean kinetic temperature was 33 degrees C. HPLC and ultraviolet spectrophotometry found drugs losses of about 7% occurred over the 28-day test period.
ReferencesAllegra JR, Brennan J, Lanier V, et al. Storage temperatures of out-of-hospital medications. Acad Emerg Med. 1999; 6
ReferencesBrown LH, Bailey LC, Medwick T, et al. Medication storage on US ambulances: a prospective multi-center observational study. Pharm Forum. 2003; 29
ReferencesCasto DT. Stability of ondansetron stored in polypropylene syringes. Ann Pharmacother. 1994; 28
ReferencesGammon DL, Su S, Huckfeldt R, et al. Alteration in prehospital drug concentration after thermal exposure. Am J Emerg Med. 2008; 26
ReferencesGraham CL, Dukes GE, Kao CF, et al. Stability of ondansetron in large-volume parenteral solutions. Ann Pharmacother. 1992; 26
ReferencesHagan RL, Mallett MS, Fox JL. Stability of ondansetron hydrochloride and dexamethasone sodium phosphate in infusion bags and syringes for 32 days. Am J Health-Syst Pharm. 1996; 53
ReferencesLeak RE, Woodford JD. Pharmaceutical development of ondansetron injection. Eur J Cancer Clin Oncol. 1989; 25
ReferencesStiles ML, Allen LV Jr, Fox JL. Stability of ondansetron hydrochloride in portable infusion-pump reservoirs. Am J Hosp Pharm. 1992; 49
ReferencesTsui BCH, Cave D. Discoloration of parenteral ondansetron. Anesth Analg. 2003; 96
pH Effects
Ondansetron hydrochloride has a natural pH of around 4.5 in aqueous solution. However, it is sensitive to increases in pH and subject to precipitation if the pH increases sufficiently. Ondansetron free base may precipitate from solution if the pH rises to the range of 5.7 to 7. Jarosinski reported that titrating the pH back down with hydrochloric acid redissolved the precipitate. Contact of ondansetron hydrochloride solutions with alkaline drugs and solutions that may raise the solution pH should be avoided.
ReferencesJarosinski PF, Hirschfeld S. Precipitation of ondansetron in alkaline solutions. N Eng J Med. 1991; 325
ReferencesLeak RE, Woodford JD. Pharmaceutical development of ondansetron injection. Eur J Cancer Clin Oncol. 1989; 25
ReferencesMacKinnon JWM, Collin DT. The chemistry of ondansetron. Eur J Cancer Clin Oncol. 1989; 25
ReferencesTrissel LA, Tramonte SM, Grilley BJ. Visual compatibility of ondansetron hydrochloride with other selected drugs during simulated Y-site injection. Am J Hosp Pharm. 1991; 48
Light Exposure
Ondansetron hydrochloride should be protected from exposure to light for long-term storage. Leak and Woodford reported that while ondansetron hydrochloride is unstable if exposed to sufficiently intense light, the drug was stable for about a month exposed to mixed daylight and fluorescent light.
ReferencesLeak RE, Woodford JD. Pharmaceutical development of ondansetron injection. Eur J Cancer Clin Oncol. 1989; 25
ReferencesZofran (ondansetron) injection package insert. East Hanover, NJ. Novartis Pharmaceuticals Corporation. 2021; Oct
Freezing
Bosso et al. reported that ondansetron 0.03 and 0.3 mg/mL as hydrochloride in dextrose 5% and in sodium chloride 0.9% was stable for 3 months frozen at -20 degrees C. Stability-indicating HPLC analysis found about 5 to 10% loss of ondansetron hydrochloride over 3 months of frozen storage. Blaise et al. reported that ondansetron 0.08 mg/mL as hydrochloride in sodium chloride 0.9% was physically and chemically stable frozen at -20 degrees C for 120 days. HPLC analysis found less than 4% drug loss occurred.
ReferencesBlaise N, Vigneron J, Perrin A, et al. Stability of refrigerated and frozen solutions of ondansetron hydrochloride. Eur J Hosp Pharm. 1994; 4
ReferencesBosso JA, Prince RA, Fox JL. Stability of ondansetron hydrochloride in injectable solutions at -20, 5, and 25 degree C. Am J Hosp Pharm. 1992; 49
Filtration
Liao et al. reported that Glaxo ondansetron 0.03 and 0.2 mg/mL as hydrochloride in sodium chloride 0.9% did not exhibit binding to several 0.2-micron inline filters including Abbott Ivex-HP Filterset-SL, Baxter Continu-Flo, Burron filter extension sets models PFE-2007 and FE-2024, and IVAC Universal Primary infusion set.
ReferencesLiao E, Fox JL, Dukes GE. Inline filtration of ondansetron hydrochloride during simulated iv administration. Am J Hosp Pharm. 1993; 50
Sorption Leaching
Ondansetron hydrochloride has not been found to undergo substantial sorption to polyvinyl chloride (PVC), polypropylene (syringes and bags), or glass containers, or to elastomeric pump reservoirs. In addition, Xu et al. reported no sorption occurred to a polyurethane central catheter from Arrow International as well as no leaching of the chlorhexidine antimicrobial in it.
ReferencesAnon. Manufacturer's information and labeling. (Package insert).
ReferencesAnon. Drug stability data for Intermate and Infusor portable elastomeric infusion devices. Round Lake, IL: Baxter Healthcare Corporation.. 2008;
ReferencesAnon. ReadyMed drug stability/system compatibility, San Diego, CA: Alaris Medical Systems. 1997;
ReferencesBlaise N, Vigneron J, Perrin A, et al. Stability of refrigerated and frozen solutions of ondansetron hydrochloride. Eur J Hosp Pharm. 1994; 4
ReferencesBosso JA, Prince RA, Fox JL. Stability of ondansetron hydrochloride in injectable solutions at -20, 5, and 25 degree C. Am J Hosp Pharm. 1992; 49
ReferencesCasto DT. Stability of ondansetron stored in polypropylene syringes. Ann Pharmacother. 1994; 28
ReferencesGraham CL, Dukes GE, Kao CF, et al. Stability of ondansetron in large-volume parenteral solutions. Ann Pharmacother. 1992; 26
ReferencesHagan RL, Mallett MS, Fox JL. Stability of ondansetron hydrochloride and dexamethasone sodium phosphate in infusion bags and syringes for 32 days. Am J Health-Syst Pharm. 1996; 53
ReferencesJhee SS, Jeong EWS, Chin A, et al. Stability of ondansetron hydrochloride stored in a disposable, elastomeric infusion device at 4 degree C. Am J Hosp Pharm. 1993; 50
ReferencesLeak RE, Woodford JD. Pharmaceutical development of ondansetron injection. Eur J Cancer Clin Oncol. 1989; 25
ReferencesXu QA, Zhang Y, Trissel LA, et al. Adequacy of a new chlorhexidine-bearing polyurethane central catheter for administration of 82 selected parenteral drugs. Ann Pharmacother. 2000; 34
Stability Max
Maximum reported stability periods: In D5W- 14 days at room temperature and 30 days refrigerated In NS- 14 days at room temperature and 30 days refrigerated
ReferencesGraham CL, Dukes GE, Kao CF, et al. Stability of ondansetron in large-volume parenteral solutions. Ann Pharmacother. 1992; 26
ReferencesHagan RL, Mallett MS, Fox JL. Stability of ondansetron hydrochloride and dexamethasone sodium phosphate in infusion bags and syringes for 32 days. Am J Health-Syst Pharm. 1996; 53
ReferencesLeak RE, Woodford JD. Pharmaceutical development of ondansetron injection. Eur J Cancer Clin Oncol. 1989; 25
Revision Date: 03/10/2017, 11:15:50 AMCopyright 2004-2023 by Lawrence A. Trissel. All Rights Reserved.

References

31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.41272 - Zuplenz (ondansetron) package insert. Woodcliff Lake, NJ: Par Pharmaceutical, Inc.; 2021 Aug.49444 - Ondansetron hydrochloride (Zofran) tablets and oral solution package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.52214 - Casto DT. Stability of ondansetron stored in polypropylene syringes. Ann Pharmacother 1994;28:712-714.

Adverse Reactions

Moderate

  • angina
  • blurred vision
  • chest pain (unspecified)
  • constipation
  • dyspnea
  • dystonic reaction
  • elevated hepatic enzymes
  • hypokalemia
  • hypotension
  • palpitations
  • premature ventricular contractions (PVCs)
  • QT prolongation
  • sinus tachycardia
  • ST-T wave changes
  • supraventricular tachycardia (SVT)
  • urinary retention

Mild

  • agitation
  • anxiety
  • chills
  • diarrhea
  • dizziness
  • drowsiness
  • fatigue
  • fever
  • flushing
  • headache
  • hiccups
  • injection site reaction
  • malaise
  • paresthesias
  • pruritus
  • rash
  • syncope
  • urticaria

Severe

  • acute myocardial ischemia
  • anaphylactoid reactions
  • angioedema
  • atrial fibrillation
  • AV block
  • bradycardia
  • bronchospasm
  • cardiac arrest
  • coronary vasospasm
  • hepatic failure
  • laryngeal edema
  • laryngospasm
  • respiratory arrest
  • seizures
  • serotonin syndrome
  • Stevens-Johnson syndrome
  • torsade de pointes
  • toxic epidermal necrolysis
  • ventricular tachycardia
  • visual impairment

Diarrhea (2—16%) and constipation (6—11%) were among the most frequently reported adverse events in patients receiving ondansetron during clinical trials for chemotherapy-induced nausea and vomiting (CINV) with moderate-high emetogenic agents.[31266] [49444] Hiccups have been reported during post-marketing experience with ondansetron.[31266]

Urinary retention (5%) and gynecological disorder (7%) have been reported in patients receiving oral ondansetron for postoperative nausea and vomiting (PONV) during clinical trials.[49444]

Headache (9—27%) was the most frequently reported adverse event during clinical trials of ondansetron and appeared to be more common in patients receiving the drug for chemotherapy-induced nausea and vomiting (CINV). Preliminary observations in a small number of subjects suggest a higher incidence of headache when ondansetron orally disintegrating tablets are taken with water, when compared to without water. Other neurologic side effects reported include drowsiness (8—20%), malaise and fatigue (9—13%), anxiety or agitation (<= 6%), paresthesias (2%), and dizziness (4—7%). Transient dizziness associated with intravenous infusion has been reported post-marketing. Rarely, extrapyramidal reactions, including oculogyric crisis appearing alone or with other types of dystonic reaction, have been reported with ondansetron use.[31266] [49444] In one case, extrapyramidal reactions were confirmed by rechallenge.[31899] In addition, there have been rare reports of grand mal seizures in patients receiving ondansetron, although a casual relationship has not been established.[31266]

Elevated hepatic enzymes were reported in patients receiving either cisplatin- or cyclophosphamide-based chemotherapy during clinical trials. The elevation did not appear to be related to ondansetron dose or duration of therapy. The enzyme levels exceeded twice the upper limit of normal (ULN) in approximately 5% of chemotherapy patients receiving injection dosing, and 1—2% of patients receiving oral therapy, but the increases were transient in nature and did not cause symptomatic hepatic disease. Repeat exposure showed similar elevations in some instances. In addition, hepatic failure and death have been reported in patients with cancer receiving concomitant medications including potentially hepatotoxic cytotoxic chemotherapy and antibiotics; the etiology of the hepatic failure is unclear.[31266] [49444]

Rare cases of hypokalemia have been reported following treatment with ondansetron in oncology patients; the relationship to ondansetron is unclear.[31266] [49444] It may be prudent to monitor serum electrolytes in select patients, as hypokalemia is a risk factor for electrocardiogram (ECG) changes.[31266] [49444]

Ondansetron has been associated with QT prolongation and torsade de pointes. Patients at risk for developing torsade de pointes include those with underlying heart conditions, such as congenital long QT syndrome (avoid use), those who are predisposed to hypokalemia and hypomagnesemia, and those taking other medications that lead to QT prolongation.[45648] Other cardiovascular adverse events reported during clinical trials with ondansetron include angina, chest pain (unspecified), ECG alterations (including second-degree AV block, QT prolongation, and ST-T wave changes), hypotension (5%), and sinus tachycardia. Bradycardia (6% vs. 6% placebo) was reported in patients receiving oral ondansetron for postoperative nausea and vomiting (PONV). Syncope, palpitations, and arrhythmias, including ventricular tachycardia and supraventricular tachycardia (SVT), bradycardia, premature ventricular contractions (PVCs), atrial fibrillation, and acute myocardial ischemia have been reported during postmarketing use of ondansetron. In some cases, predominantly during intravenous administration, the symptoms of myocardial ischemia appeared immediately after administration but resolved with prompt treatment. Coronary vasospasm (coronary artery spasm) appears to be the most common cause of the ischemia. To minimize the risk of these adverse events in patients receiving intravenous treatment, do not exceed the recommended ondansetron infusion rate and monitor patients for signs and symptoms of myocardial ischemia during and after administration. In patients receiving oral therapy, monitor or advise patients of these symptoms.[31266] [49444] Intravenous (IV) ondansetron given as a single 32 mg dose causes QT prolongation in a dose-dependent manner; therefore, single IV doses should not exceed 16 mg/dose IV; the 32 mg IV single-dose regimen is no longer indicated for chemotherapy-induced nausea and vomiting (CINV). Oral dosing recommendations have not changed.[51100] ECG monitoring is recommended in patients with electrolyte imbalance (e.g., hypokalemia or hypomagnesemia), congestive heart failure, significant bradycardia, or in patients taking other medications that can lead to QT prolongation.[31266] [49444] [45648]

Several reports of anaphylactoid reactions have been associated with serotonin (5-HT3) receptor antagonists, such as ondansetron.[23534] [52212] Manifestations of anaphylactoid reactions have included angioedema, bronchospasm, dyspnea, hypotension, laryngeal edema, stridor, and/or urticaria. Laryngospasm, shock, cardiac arrest, and respiratory arrest have been reported during allergic reactions in patients receiving injectable ondansetron. Rash (unspecified) (1%), pruritus (2—5%), and flushing have been reported in clinical trials with both oral and injectable formulations.[31266] [49444] Stevens-Johnson syndrome and toxic epidermal necrolysis (TENS) have been reported with post-marketing use of ondansetron.[31266] [49444]

An injection site reaction (4%) was reported in patients receiving ondansetron injection intravenously over 2 to 5 minutes during clinical trials for post-operative nausea/vomiting (PONV); symptoms included pain, erythema, and burning at the site.[31266]

Visual impairment has occurred with ondansetron use. Cases of transient blindness, predominantly during intravenous (IV) administration, have been reported; resolution occurred within minutes up to 48 hours. Sudden blindness (amaurosis) of 2—3 minute duration occurred in one patient who was administered ondansetron 72 mg IV as a single dose.[49444] [31266] In another case, transient blindness was reported in a patient who received ondansetron 4mg as a post-operative rapid IV bolus dose.[31837] The mechanism by which ondansetron may cause visual impairment is not well understood. Clinicians in the latter case suggest that it may be related to the rate of administration. Transient blurred vision, in some cases associated with accommodation disorder, has also been reported during post-marketing experience.[31266]

Fever (2—8%) and shivers or chills (2—5%) were reported in patients receiving ondansetron during clinical trials. Wound problems (28% vs. 31% placebo) were reported in patients receiving oral ondansetron for postoperative nausea and vomiting (PONV).[31266] [49444]

Serotonin syndrome has been reported with 5-HT3 receptor antagonists, such as ondansetron, during concurrent use of other medications known to increase CNS or peripheral serotonin levels or during overdose. Some of the reported cases were fatal; most occurred in a post-anesthesia care unit or infusion center. If serotonin syndrome becomes evident during treatment, discontinue ondansetron and any other serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is a range of signs and symptoms that can include mental status changes (e.g., agitation, hallucinations, delirium, coma), gastrointestinal symptoms (e.g., nausea, vomiting, diarrhea), autonomic instability (e.g., tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular symptoms (e.g., tremor, rigidity, myoclonus, hyperreflexia, incoordination), and/or seizures. Cases consistent with serotonin syndrome have been reported in pediatric patients after inadvertent overdose of oral ondansetron (estimated ingestion > 5 mg/kg). Symptoms reported in these cases included somnolence, agitation, tachycardia, tachypnea, hypertension, flushing, mydriasis, diaphoresis, myoclonic movements, horizontal nystagmus, hyperreflexia, and seizures. Patients required supportive care, including intubation in some cases, with complete recovery in 1—2 days.[31266] [49444]

Revision Date: 10/27/2021, 09:15:48 AM

References

23534 - Chen M, Tanner A, Gallo-Torres H. Anaphylactoid-anaphylactic reactions associated with ondansetron. Ann Intern Med 1993;119:862.31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.31837 - Cherian A, Maguire M. Transient blindness following intravenous ondansetron. Anaesthesia 2005;60:938-9.31899 - Stonell C. An extrapyramidal reaction to ondansetron. Br J Anaesth 1998;81:658.45648 - Food and Drug Administration (US FDA) MedWatch. Zofran (ondansetron): Drug safety communication-Risk of Abnormal Heart Rhythms. Retrieved Sept. 15, 2011. Available on the World Wide Web at http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm272041.htm49444 - Ondansetron hydrochloride (Zofran) tablets and oral solution package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.51100 - FDA Drug Safety Communication: Ondansetron (Zofran) IV-QT prolongation. Retrieved June 29, 2012. Available on the World Wide Web at: http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm310219.htm?source=govdelivery.52212 - Kataja V, Bruijn. Hypersensitivity reactions associated with 5-hydroxytriptamine3-receptor antagonists: a class effect? Lancet 1996;347:584-585.

Contraindications/Precautions

Absolute contraindications are italicized.

  • ondansetron hypersensitivity
  • apheresis
  • AV block
  • bradycardia
  • breast-feeding
  • cardiomyopathy
  • celiac disease
  • children
  • dolasetron hypersensitivity
  • females
  • fever
  • geriatric
  • GI obstruction
  • granisetron hypersensitivity
  • heart failure
  • hepatic disease
  • hepatitis
  • human immunodeficiency virus (HIV) infection
  • hyperparathyroidism
  • hypocalcemia
  • hypokalemia
  • hypomagnesemia
  • hypothermia
  • hypothyroidism
  • ileus
  • infants
  • long QT syndrome
  • myocardial infarction
  • neonates
  • palonosetron hypersensitivity
  • phenylketonuria
  • pheochromocytoma
  • pregnancy
  • QT prolongation
  • rheumatoid arthritis
  • sickle cell disease
  • sleep deprivation
  • stroke
  • systemic lupus erythematosus (SLE)

The fixed dose of ondansetron recommended for post-operative nausea and vomiting was established in patients weighing less than 80 kg. Patients weighing more than 80 kg or with obesity have not been studied extensively.

Ondansetron is extensively metabolized in the liver and should be used with caution in patients with hepatic disease, hepatitis, or elevated hepatic enzymes because of possible increased plasma levels, reduced clearance, and subsequent toxicity.[31266]

Ondansetron should not be used in patients with a known ondansetron hypersensitivity. Use with caution in patients with known granisetron hypersensitivity, palonosetron hypersensitivity, dolasetron hypersensitivity, or sensitivity to related drugs.[31266] Cross-sensitivity is possible between these agents; there have been several reports of anaphylactic/anaphylactoid reactions associated with the use of drugs in this class.[23534] [52212] Antagonism at serotonin (5-HT) receptors, and the subsequent increased concentrations of serotonin, may increase the risk of developing bronchospasm and/or vasoconstriction.[52208] [52210] [52211]

Patients with phenylketonuria should be informed that ondansetron orally disintegrating tablets (ODT) contain phenylalanine (a component of aspartame). Each 4 mg and 8 mg ODT contains less than 0.03 mg phenylalanine.[31266]

The use of ondansetron may mask the symptoms of adynamic ileus, GI obstruction, or gastric distention after abdominal surgery or during use to prevent chemotherapy-induced nausea and vomiting.[31266] Ondansetron is not a drug that stimulates gastric or intestinal peristalsis; it should not be used instead of nasogastric suction.[41272]

Myocardial ischemia has been reported in patients treated with ondansetron. In some cases, predominantly during intravenous administration, the symptoms appeared immediately after administration but resolved with prompt treatment. Coronary artery spasm (coronary vasospasm) appears to be the most common underlying cause. Therefore, monitor for or advise patients of signs or symptoms of myocardial ischemia during use of ondansetron.[31266] [49444] Ondansetron also increases the risk of developing QT prolongation in a dose-dependent manner, which can lead to abnormal and potentially fatal heart rhythms, including torsade de pointes. In June 2012, the FDA announced preliminary results from a study suggesting that intravenous (IV) ondansetron given as a single 32 mg dose causes QT prolongation. Single IV doses should not exceed 16 mg; the 32 mg IV single-dose regimen is no longer indicated for chemotherapy-induced nausea and vomiting prophylaxis. Oral dosing recommendations have not changed and the use of single oral doses up to 24 mg may be used for the prevention of chemotherapy-induced nausea and vomiting (CINV). Avoid ondansetron in patients with congenital long QT syndrome. Electrocardiogram (ECG) monitoring and cautious use is recommended in patients with hypokalemia, hypomagnesemia, congestive heart failure, significant bradycardia, or in patients taking other medications known to prolong the QT interval. Use ondansetron with caution in patients with conditions that may increase the risk of QT prolongation including bradycardia, AV block, stress-related cardiomyopathy, myocardial infarction, stroke, hypocalcemia, or in patients receiving medications known to cause electrolyte imbalances. Females, people 65 years and older, patients with sleep deprivation, pheochromocytoma, sickle cell disease, hypothyroidism, hyperparathyroidism, hypothermia, systemic inflammation (e.g., human immunodeficiency virus (HIV) infection, fever, and some autoimmune diseases including rheumatoid arthritis, systemic lupus erythematosus (SLE), and celiac disease) and patients undergoing apheresis procedures (e.g., plasmapheresis [plasma exchange], cytapheresis) may also be at increased risk for QT prolongation.[28432] [28457] [51100] [56592] [65180] [31266] [49444]

Little information is available about dosage in children 4 years of age or younger. Furthermore, there is no experience with the use of 24 mg ondansetron tablets in pediatric patients.[31266] [49444]

Infants younger than 4 months of age may accumulate ondansetron and should be closely monitored for toxicity. Limited information is available on the use of ondansetron in neonates younger than 1 month of age receiving surgery or in pediatric cancer patients who are infants younger than 6 months of age. The clearance of ondansetron in infants 1 to 4 months of age is slower and the half-life is roughly 2.5-fold longer than infant patients who are 4 to 24 months of age.[31266]

Data on the use of ondansetron during human pregnancy from published clinical and epidemiological studies are inconsistent and have important methodological limitations, including the uncertainty of whether women who filled a prescription actually took the medicine, the concomitant use of other medications or treatments, recall bias, and other unadjusted confounders, that do not reliably inform a drug associated risk of adverse fetal outcomes. In aggregate analysis, ondansetron exposure in utero has not been associated with major congenital malformations. Some studies have not shown a statistically significant increase in the risk of birth defects with the use of ondansetron; however, others have shown a possible increased risk of cleft palate and cardiovascular malformations.[31266] [46607] [49444] [59645] [59647] [59650] [59651] Ondansetron has been shown to cross the placenta in early pregnancy with a median fetal to maternal ratio of 0.41.[46606] Evidence is limited on the safety or efficacy of the serotonin 5-HT3 inhibitors for nausea and vomiting of pregnancy. There are more published data for ondansetron use during pregnancy than with other 5HT-3 antagonists. The American College of Obstetricians and Gynecologists (ACOG) includes oral ondansetron as a third-line pharmacologic treatment option for nausea and vomiting of pregnancy in patients who are not dehydrated and have failed other therapies and IV ondansetron for patients who are dehydrated, require IV fluid replacement, and have failed other therapies. Although some studies have shown an increased risk of birth defects with early ondansetron use, other studies have not and the absolute risk to any fetus is considered, per ACOG, to be low. Some studies have suffered from small sample sizes and potential methodological bias. However, women should be counseled regarding the available data, and the use of ondansetron before 10 weeks of gestation should be individualized weighing the risks and benefits.[66066] [59650] [59651] [59647]

It is not known whether ondansetron is excreted in human milk. However, because of its low molecular weight, transfer into breast milk should be expected.[31726] Caution should be exercised when administering ondansetron to a breast-feeding woman.

No differences in responses for safety or efficacy have been observed between geriatric and younger patients during clinical trials or other reported clinical experience. Of the total number of patients enrolled in US and foreign-controlled clinical trials for postoperative and chemotherapy-induced nausea and vomiting, for which there were subgroup analyses, 938 were 65 years of age or older. However, greater sensitivity of some older individuals cannot be ruled out. The manufacturer states that no dosage adjustments are needed in elderly patients. Geriatric patients may be at increased risk for developing a prolonged QT interval when using ondansetron.[28432] [28457] [31266] [56592] [65180]

Revision Date: 10/27/2021, 09:21:28 AM

References

23534 - Chen M, Tanner A, Gallo-Torres H. Anaphylactoid-anaphylactic reactions associated with ondansetron. Ann Intern Med 1993;119:862.28432 - Roden, DM. Drug-induced prolongation of the QT interval. New Engl J Med 2004;350:1013-22.28457 - Crouch MA, Limon L, Cassano AT. Clinical relevance and management of drug-related QT interval prolongation. Pharmacotherapy 2003;23:881-908.31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.31726 - Drugs in Pregnancy and Lactation. A Reference Guide to Fetal and Neonatal Risk. Briggs GG, Freeman RK, Yaffe SJ, (eds.) 7th ed., Philadelphia PA: Lippincott Williams and Wilkins 2005;:742-3.41272 - Zuplenz (ondansetron) package insert. Woodcliff Lake, NJ: Par Pharmaceutical, Inc.; 2021 Aug.46606 - Siu SN, Chan M, Lau T. Placental transfer of ondansetron during early human pregnancy. Clin Pharmacokinet 2006;45:419-23.46607 - Einarson A, Maltepe C, Navioz Y, et al. The safety of ondansetron for nausea and vomiting of pregnancy: a prospective comparative study. BJOG 2004;111:940-3.49444 - Ondansetron hydrochloride (Zofran) tablets and oral solution package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.51100 - FDA Drug Safety Communication: Ondansetron (Zofran) IV-QT prolongation. Retrieved June 29, 2012. Available on the World Wide Web at: http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm310219.htm?source=govdelivery.52208 - Cazzola M, Matera MG. 5-HT modifiers as a potential treatment of asthma. Trends Pharmacol Sci 2000;21:13-16.52210 - Tsuneyuki T, Ward JK, Tadjkarimi S. 5-hydroxytryptamine facilitates cholinergic bronchoconstriction in human and guinea pig airways. Am J Respir Care Med 1995;152:377-380.52211 - Saxena PR, Villalon CM. Cardiovascular effects of serotonin agonists and antagonists. J Cardiovasc Pharmacol 1991;15: S17-34.52212 - Kataja V, Bruijn. Hypersensitivity reactions associated with 5-hydroxytriptamine3-receptor antagonists: a class effect? Lancet 1996;347:584-585.56592 - van Noord C, Eijgelsheim M, Stricker BH. Drug- and non-drug-associated QT interval prolongation. Br J Clin Pharmacol 2010;70(1):16-23.59645 - Colvin L, Gill AW, Slack-Smith L, et al. Off-label use of ondansetron in pregnancy in western Australia. BioMed Res Int 2013. Epub ahead of print, doi: 10.1155/2013/909860.59647 - Pasternak B, Svanstrom H, Hviid A. Ondansetron in pregnancy and risk of adverse fetal outcomes. N Engl J Med 2013;368:814-23.59650 - Danielsson B, Wikner BN, Kallen B. Use of ondansetron during pregnancy and congenital malformations in the infant. Reprod Toxicol 2014;50:134-7.59651 - Anderka M, Mitchell AA, Louik C, et al. Medications used to treat nausea and vomiting of pregnancy and the risk of selected birth defects. Birth defects Res A Clin Mol Teratol 2012;94:22-30.65180 - Woosley RL, Heise CW, Gallo T, et al. QTFactors List. Oro Valley, AZ: AZCERT, Inc.; Accessed March 31, 2020. Available on the World Wide Web at: https://crediblemeds.org/ndfa-list/66066 - American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin Number 189: Nausea and vomiting of pregnancy. Obstet Gynecol 2018;131:15-30. Reaffirmed 2019.

Mechanism of Action

Ondansetron is a 5-HT3 receptor antagonist. Although other neurotransmitters are involved, serotonin plays an important role in the emetogenic pathways associated with chemotherapy- and radiation-induced nausea and vomiting. During the early or acute phase, the primary site of emetogenesis in chemotherapy-induced nausea and vomiting (CINV) is thought to be the gut wall. Chemotherapy is cytotoxic to enterochromaffin cells in the small intestine. Enterochromaffin cell death leads to serotonin release and therefore increased serotonin binding on nerve endings, leading to sensory input that contributes to emesis.[52167][52168] Peripherally, ondansetron preferentially blocks the serotonin 5-hydroxytryptamine, type 3 (5-HT3) receptors at the peripheral vagal nerve terminals in the intestines, blocking the signal transmission to the central nervous system and antagonizing the effects of serotonin. Ondansetron is also a weak antagonist of the 5-HT1B, 5-HT1C, alpha-adrenergic, and opioid mu receptors; the clinical implications of these actions is uncertain. It has no activity at dopamine receptors.[31266][52167]

 

Much like chemotherapy-induced nausea and vomiting (CINV), postoperative nausea and vomiting (PONV) is not controlled by a single neurotransmitter, but serotonin is believed to play a major role. The process of postoperative nausea and vomiting is coordinated by the vomiting center in the central nervous system. Stimulation can be initiated centrally in areas such as the cerebral cortex and otic or vestibular nerves, or peripherally in areas such as the oropharynx, mediastinum, gastrointestinal track, renal pelvis, peritoneum, or genitalia. Stretching and inflammation that occur during or after surgery may trigger chemical stimulation that lead to nausea and vomiting. Centrally, ondansetron blocks the 5-HT3 receptor site at the chemoreceptor trigger zone, stopping the vomiting reflex produced by the vomiting center. Because of multiple neurochemical receptor sites involved during surgery, combination antiemetic therapy with drugs of different mechanisms is often necessary.[31266][52169]

Revision Date: 10/29/2012, 02:47:53 PM

References

31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.52167 - Culy CR, Bhana N, Plosker GL. Ondansetron: a review of its use as an antiemetic in children. Paediatr Drug 2001;3:441-479.52168 - Rojas C, Slusher BS. Pharmacological mechanisms of 5-HT3 and tachykinin NK1 receptor antagonism to prevent chemotherapy-induced nausea and vomiting. Eur J Pharmacol 2012;684:1-7.52169 - Kovac AL. Management of postoperative nausea and vomiting in children. Paediatr Drugs 2007;9:47-69.

Pharmacokinetics

Ondansetron is administered orally and parenterally. It is approximately 70—76% bound to plasma protein; circulating drug also distributes into erythrocytes (approximately 36%). Animal data indicate it distributes into breast milk. Systemic exposure does not increase proportionately to the dose. Less than 5% of a dose is excreted in the urine unchanged. The mean elimination half-life in adults ranges 3.1 to 5.8 hours.[31266][49444]

 

Affected cytochrome P450 isoenzymes and drug transporters:  CYP3A4, CYP1A2, CYP2D6, CYP2C9, P-gp

Ondansetron undergoes extensive metabolism, mainly by hydroxylation, followed by glucuronide or sulfate conjugation. In vitro studies indicate that ondansetron is metabolized by hepatic cytochrome P450 (CYP450) drug-metabolizing enzymes, including CYP1A2, CYP2D6, and CYP3A4; with CYP3A4 playing the largest role. Because multiple enzymes are involved in the metabolism of ondansetron, inhibition or loss of any one enzyme may not affect the overall rate of metabolism. Additionally, it is likely that inhibition or loss of one enzyme (e.g., CYP2D6 genetic deficiency) will be compensated by others and may result in little change in overall rates of ondansetron elimination.[31266] Interactions with inhibitors or inducers of these enzymes have not been reported clinically; however, the potential exists for these interactions to change the clearance and, hence, the half-life of ondansetron. On the basis of limited available data, no dosage adjustment is recommended for patients receiving CYP-interacting drugs. Ondansetron is also a substrate of P-glycoprotein.[31266][34653] The inactive metabolites are eliminated in the urine.

Route-Specific Pharmacokinetics

Oral Route

Following oral administration, ondansetron is well absorbed from the gastrointestinal tract and undergoes first-pass metabolism. After a dose of a single 8-mg tablet, mean oral bioavailability in healthy adult subjects is 56%. The AUC from a 16 mg-tablet is 24% greater than predicted from an 8-mg tablet dose, indicating reduced first-pass metabolism at higher oral doses. Food slightly enhances tablet bioavailability, but antacids have no effect. Of note, 4- and 8-mg oral ondansetron tablets, orally disintegrating tablets (ODT), and oral solution are bioequivalent.[49444] After a single 8-mg dose of ondansetron oral soluble film in adult patients, peak plasma concentrations are achieved in 1.3 hours, and mean Cmax is 37.28 ng/mL and the mean AUC 225 n x h/mL. The Cmax and AUC of the oral soluble film is comparable to that of the same dose of ondansetron ODT. Water does not affect the exposure of ondansetron oral soluble film administration. Administration of the oral soluble film with a high-fat meal delays the Tmax by approximately 1 hour, but the AUC is unaffected.[41272]

Intravenous Route

In adults, a single 4-mg dose administered as a 5-minute intravenous (IV) infusion demonstrated a mean AUC of 156 ng x h/ml. Mean peak plasma concentrations were 42.9 ng/ml at 10 minutes after IV infusion.[31266]

Special Populations

Hepatic Impairment

In adult patients with mild to moderate hepatic impairment, ondansetron clearance is reduced two-fold and mean half-life is increased to 11.6 hours, compared to 3—5.7 hours in patients without hepatic impairment. In adult patients with severe hepatic impairment, clearance is reduced two-fold to three-fold and volume of distribution is increased, resulting in an increase in elimination half-life to 20 hours.[31266]

Renal Impairment

A small percentage (5%) of ondansetron is renally cleared. In patients with severe renal impairment (creatinine clearance < 30 ml/min) the mean plasma clearance is reduced by approximately 40%; however, the reduction is variable and is not consistent with an increase in half-life.[31266] A dose reduction is not necessary in this population.

Pediatrics

In general, pediatric patients have a higher ondansetron clearance compared to adult patients, resulting in a shorter half-life; mean half-life is approximately 2.8 hours in pediatric cancer patients 4—15 years of age; patients older than 15 years exhibit pharmacokinetic parameters similar to adults. A pharmacokinetic study of postoperative children 3—12 years of age given a single dose of 2 or 4 mg IV demonstrated an elimination half-life of 2.5—3.5 hours. Another surgical study in infants and children 5—24 months receiving 0.1—0.2 mg/kg IV ondansetron as a single dose demonstrated an elimination half-life of 2.9 hours. Notably, during the same study, infants 1—4 months of age had a higher Vd (3.5 L/kg), longer half-life (6.7 hours), and slower clearance (0.401 L/kg/h) relative to older children.[31266] During a pharmacokinetic study in infants and children age 1—48 months, simulations showed that an intravenous dose of ondansetron 0.1 mg/kg in infants < 6 months produced exposure similar to a 0.15 mg/kg dose in older infants and young children.[52159]

Geriatric

Patients over 75 years also have a reduced clearance of ondansetron and an increased elimination half-life, however, no dosage adjustments are recommended.[31266]

Gender Differences

Gender differences exist in the disposition of single-dose ondansetron. The extent and rate of ondansetron absorption is greater in women than men. Slower clearance in women, a smaller apparent volume of distribution (adjusted for weight), and higher absolute bioavailability resulted in higher plasma concentrations, which may in part be due to differences in body weight between men and women. It is not known if these gender-related differences are clinically important.[31266]

Revision Date: 04/17/2014, 09:41:50 AM

References

31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.34653 - Schinkel AH, Wagenaar E, Mol C, et al. P-glycoprotein in the blood-brain barrier of mice influences the brain penetration and pharmacological activity of many drugs. J Clin Invest 1996;97:2517-2524.41272 - Zuplenz (ondansetron) package insert. Woodcliff Lake, NJ: Par Pharmaceutical, Inc.; 2021 Aug.49444 - Ondansetron hydrochloride (Zofran) tablets and oral solution package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.52159 - Mondick JT, Johnson BM, Haberer LJ. Population pharmacokinetics of intravenous ondansetron in oncology and surgical patients aged 1-48 months. Eur J Clin Pharmacol 2010;66:77-86.

Pregnancy/Breast-feeding

pregnancy

Data on the use of ondansetron during human pregnancy from published clinical and epidemiological studies are inconsistent and have important methodological limitations, including the uncertainty of whether women who filled a prescription actually took the medicine, the concomitant use of other medications or treatments, recall bias, and other unadjusted confounders, that do not reliably inform a drug associated risk of adverse fetal outcomes. In aggregate analysis, ondansetron exposure in utero has not been associated with major congenital malformations. Some studies have not shown a statistically significant increase in the risk of birth defects with the use of ondansetron; however, others have shown a possible increased risk of cleft palate and cardiovascular malformations.[31266] [46607] [49444] [59645] [59647] [59650] [59651] Ondansetron has been shown to cross the placenta in early pregnancy with a median fetal to maternal ratio of 0.41.[46606] Evidence is limited on the safety or efficacy of the serotonin 5-HT3 inhibitors for nausea and vomiting of pregnancy. There are more published data for ondansetron use during pregnancy than with other 5HT-3 antagonists. The American College of Obstetricians and Gynecologists (ACOG) includes oral ondansetron as a third-line pharmacologic treatment option for nausea and vomiting of pregnancy in patients who are not dehydrated and have failed other therapies and IV ondansetron for patients who are dehydrated, require IV fluid replacement, and have failed other therapies. Although some studies have shown an increased risk of birth defects with early ondansetron use, other studies have not and the absolute risk to any fetus is considered, per ACOG, to be low. Some studies have suffered from small sample sizes and potential methodological bias. However, women should be counseled regarding the available data, and the use of ondansetron before 10 weeks of gestation should be individualized weighing the risks and benefits.[66066] [59650] [59651] [59647]

breast-feeding

It is not known whether ondansetron is excreted in human milk. However, because of its low molecular weight, transfer into breast milk should be expected.[31726] Caution should be exercised when administering ondansetron to a breast-feeding woman.

Revision Date: 05/03/2021, 03:51:24 PM

References

31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.31726 - Drugs in Pregnancy and Lactation. A Reference Guide to Fetal and Neonatal Risk. Briggs GG, Freeman RK, Yaffe SJ, (eds.) 7th ed., Philadelphia PA: Lippincott Williams and Wilkins 2005;:742-3.46606 - Siu SN, Chan M, Lau T. Placental transfer of ondansetron during early human pregnancy. Clin Pharmacokinet 2006;45:419-23.46607 - Einarson A, Maltepe C, Navioz Y, et al. The safety of ondansetron for nausea and vomiting of pregnancy: a prospective comparative study. BJOG 2004;111:940-3.49444 - Ondansetron hydrochloride (Zofran) tablets and oral solution package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.59645 - Colvin L, Gill AW, Slack-Smith L, et al. Off-label use of ondansetron in pregnancy in western Australia. BioMed Res Int 2013. Epub ahead of print, doi: 10.1155/2013/909860.59647 - Pasternak B, Svanstrom H, Hviid A. Ondansetron in pregnancy and risk of adverse fetal outcomes. N Engl J Med 2013;368:814-23.59650 - Danielsson B, Wikner BN, Kallen B. Use of ondansetron during pregnancy and congenital malformations in the infant. Reprod Toxicol 2014;50:134-7.59651 - Anderka M, Mitchell AA, Louik C, et al. Medications used to treat nausea and vomiting of pregnancy and the risk of selected birth defects. Birth defects Res A Clin Mol Teratol 2012;94:22-30.66066 - American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins-Obstetrics. ACOG Practice Bulletin Number 189: Nausea and vomiting of pregnancy. Obstet Gynecol 2018;131:15-30. Reaffirmed 2019.

Interactions

Level 1 (Severe)

  • Apomorphine
  • Cisapride
  • Dextromethorphan; Quinidine
  • Dronedarone
  • Fluconazole
  • Ketoconazole
  • Levoketoconazole
  • Pimozide
  • Posaconazole
  • Quinidine
  • Thioridazine

Level 2 (Major)

  • Adagrasib
  • Alfuzosin
  • Amiodarone
  • Amisulpride
  • Amoxicillin; Clarithromycin; Omeprazole
  • Anagrelide
  • Aripiprazole
  • Arsenic Trioxide
  • Artemether; Lumefantrine
  • Asenapine
  • Atomoxetine
  • Atropine; Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate
  • Azithromycin
  • Bedaquiline
  • Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate
  • Bismuth Subcitrate Potassium; Metronidazole; Tetracycline
  • Bismuth Subsalicylate; Metronidazole; Tetracycline
  • Buprenorphine
  • Buprenorphine; Naloxone
  • Cabotegravir; Rilpivirine
  • Ceritinib
  • Chloroquine
  • Chlorpromazine
  • Ciprofloxacin
  • Citalopram
  • Clarithromycin
  • Clofazimine
  • Clozapine
  • Codeine; Phenylephrine; Promethazine
  • Codeine; Promethazine
  • Crizotinib
  • Dasatinib
  • Degarelix
  • Desflurane
  • Desvenlafaxine
  • Deutetrabenazine
  • Disopyramide
  • Dofetilide
  • Dolasetron
  • Dolutegravir; Rilpivirine
  • Donepezil
  • Donepezil; Memantine
  • Droperidol
  • Efavirenz
  • Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate
  • Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate
  • Eliglustat
  • Emtricitabine; Rilpivirine; Tenofovir alafenamide
  • Emtricitabine; Rilpivirine; Tenofovir disoproxil fumarate
  • Encorafenib
  • Entrectinib
  • Eribulin
  • Erythromycin
  • Escitalopram
  • Fingolimod
  • Flecainide
  • Fluoxetine
  • Fluvoxamine
  • Foscarnet
  • Fostemsavir
  • Gemifloxacin
  • Gemtuzumab Ozogamicin
  • Gilteritinib
  • Glasdegib
  • Goserelin
  • Granisetron
  • Halogenated Anesthetics
  • Haloperidol
  • Histrelin
  • Hydroxychloroquine
  • Hydroxyzine
  • Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate
  • Ibutilide
  • Idelalisib
  • Iloperidone
  • Inotuzumab Ozogamicin
  • Ipecac
  • Isoflurane
  • Itraconazole
  • Ivosidenib
  • Lansoprazole; Amoxicillin; Clarithromycin
  • Lapatinib
  • Lefamulin
  • Lenvatinib
  • Leuprolide
  • Leuprolide; Norethindrone
  • Levofloxacin
  • Levomilnacipran
  • Linezolid
  • Lithium
  • Lofexidine
  • Loperamide
  • Loperamide; Simethicone
  • Lopinavir; Ritonavir
  • Macimorelin
  • Maprotiline
  • Mefloquine
  • Meperidine; Promethazine
  • Methadone
  • Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine
  • Methylene Blue
  • Metronidazole
  • Midostaurin
  • Mifepristone
  • Mirtazapine
  • Mobocertinib
  • Moxifloxacin
  • Nilotinib
  • Octreotide
  • Ofloxacin
  • Olanzapine
  • Olanzapine; Fluoxetine
  • Olanzapine; Samidorphan
  • Osilodrostat
  • Osimertinib
  • Oxaliplatin
  • Ozanimod
  • Pacritinib
  • Paliperidone
  • Panobinostat
  • Paroxetine
  • Pasireotide
  • Pazopanib
  • Pentamidine
  • Pimavanserin
  • Pitolisant
  • Ponesimod
  • Primaquine
  • Procainamide
  • Promethazine
  • Promethazine; Dextromethorphan
  • Promethazine; Phenylephrine
  • Propafenone
  • Quetiapine
  • Quinine
  • Ranolazine
  • Relugolix
  • Relugolix; Estradiol; Norethindrone acetate
  • Ribociclib
  • Ribociclib; Letrozole
  • Rilpivirine
  • Risperidone
  • Rolapitant
  • Romidepsin
  • Saquinavir
  • Selpercatinib
  • Sertraline
  • Sevoflurane
  • Siponimod
  • Sodium Stibogluconate
  • Solifenacin
  • Sorafenib
  • Sotalol
  • Sunitinib
  • Tacrolimus
  • Tamoxifen
  • Telavancin
  • Tetrabenazine
  • Tolterodine
  • Toremifene
  • Trazodone
  • Triclabendazole
  • Triptorelin
  • Vandetanib
  • Vardenafil
  • Vemurafenib
  • Venlafaxine
  • Vilazodone
  • Voclosporin
  • Vonoprazan; Amoxicillin; Clarithromycin
  • Voriconazole
  • Vorinostat
  • Ziprasidone

Level 3 (Moderate)

  • Acetaminophen; Caffeine; Dihydrocodeine
  • Acetaminophen; Codeine
  • Acetaminophen; Hydrocodone
  • Acetaminophen; Oxycodone
  • Alfentanil
  • Aspirin, ASA; Butalbital; Caffeine; Codeine
  • Aspirin, ASA; Carisoprodol; Codeine
  • Aspirin, ASA; Oxycodone
  • Atazanavir
  • Atazanavir; Cobicistat
  • Benzhydrocodone; Acetaminophen
  • Butalbital; Acetaminophen; Caffeine; Codeine
  • Capsaicin; Metaxalone
  • Celecoxib; Tramadol
  • Chlorpheniramine; Codeine
  • Chlorpheniramine; Dihydrocodeine; Phenylephrine
  • Chlorpheniramine; Hydrocodone
  • Cobicistat
  • Codeine
  • Codeine; Guaifenesin
  • Codeine; Guaifenesin; Pseudoephedrine
  • Daclatasvir
  • Darunavir
  • Darunavir; Cobicistat
  • Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide
  • Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir
  • Duloxetine
  • Elbasvir; Grazoprevir
  • Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide
  • Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate
  • Etravirine
  • Fenfluramine
  • Fentanyl
  • Fosamprenavir
  • Glecaprevir; Pibrentasvir
  • Guaifenesin; Hydrocodone
  • Guaifenesin; Hydrocodone; Pseudoephedrine
  • Homatropine; Hydrocodone
  • Hydrocodone
  • Hydrocodone; Ibuprofen
  • Hydrocodone; Pseudoephedrine
  • Hydromorphone
  • Ibuprofen; Oxycodone
  • Isavuconazonium
  • Isocarboxazid
  • Lasmiditan
  • Ledipasvir; Sofosbuvir
  • Levorphanol
  • Meperidine
  • Metaxalone
  • Mirabegron
  • Monoamine oxidase inhibitors
  • Morphine
  • Morphine; Naltrexone
  • Nalbuphine
  • Nirmatrelvir; Ritonavir
  • Oliceridine
  • Ombitasvir; Paritaprevir; Ritonavir
  • Oxycodone
  • Oxymorphone
  • Phenelzine
  • Remifentanil
  • Ritonavir
  • Selegiline
  • Sofosbuvir; Velpatasvir; Voxilaprevir
  • Sufentanil
  • Tapentadol
  • Tolvaptan
  • Tramadol
  • Tramadol; Acetaminophen
  • Tranylcypromine

Level 4 (Minor)

  • Aprepitant, Fosaprepitant
  • Barbiturates
  • Fluphenazine
  • Fosphenytoin
  • Isoniazid, INH; Pyrazinamide, PZA; Rifampin
  • Isoniazid, INH; Rifampin
  • Lumacaftor; Ivacaftor
  • Mitotane
  • Omeprazole; Amoxicillin; Rifabutin
  • Oritavancin
  • Perphenazine
  • Perphenazine; Amitriptyline
  • Phenytoin
  • Prochlorperazine
  • Rifabutin
  • Rifampin
  • St. John's Wort, Hypericum perforatum
  • Trifluoperazine
  • Zonisamide
Acetaminophen; Caffeine; Dihydrocodeine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dihydrocodeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [30282] [31266] [31723] [49446] [58572] Acetaminophen; Codeine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Acetaminophen; Hydrocodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Acetaminophen; Oxycodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering oxycodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43906] [44061] [49446] [60634] [61107] Adagrasib: (Major) Concomitant use of adagrasib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [68325] Alfentanil: (Moderate) If concomitant use of alfentanil and ondansetron is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. [30072] Alfuzosin: (Major) Concomitant use of ondansetron and alfuzosin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28261] [31266] [32722] Amiodarone: (Major) If possible, avoid coadministration of amiodarone and ondansetron. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of torsade de pointes (TdP). If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. Amiodarone, a Class III antiarrhythmic agent, is associated with a well-established risk of QT prolongation and TdP. Although the frequency of TdP is less with amiodarone than with other Class III agents, amiodarone is still associated with a risk of TdP. Due to the extremely long half-life of amiodarone, a drug interaction is possible for days to weeks after discontinuation of amiodarone. In addition, amiodarone may inhibit ondansetron metabolism via multiple pathways (CYP1A2, CYP2D6, CYP3A4, P-glycoprotein), increasing the potential for ondansetron-related adverse events. [28224] [28432] [28457] [28896] [31266] [59321] Amisulpride: (Major) Concomitant use of ondansetron and amisulpride increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [65068] Amoxicillin; Clarithromycin; Omeprazole: (Major) Concomitant use of ondansetron and clarithromycin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28225] [28238] [31266] [32722] Anagrelide: (Major) Concomitant use of ondansetron and anagrelide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [30163] [30802] [31266] Apomorphine: (Contraindicated) The concurrent use of apomorphine and serotonin-receptor antagonists is contraindicated due to the possibility of an excessive lowering of blood pressure and unconsciousness. Additionally, additive QT prolongation is possible during coadministration of apomorphine with dolasetron, granisetron, and ondansetron. [28661] [31266] [31723] [31909] [42844] [59321] Aprepitant, Fosaprepitant: (Minor) Aprepitant, fosaprepitant is indicated for the prophylaxis of chemotherapy-induced nausea/vomiting in combination with a 5HT3 antagonist, one of which is ondansetron. Ondansetron is a CYP3A4 substrate. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer; substitution of fosaprepitant 115 mg IV on day 1 of the 3-day regimen may lessen the inhibitory effects of CYP3A4. The AUC of another CYP3A4 substrate, midazolam, was increased for several days after aprepitant dosing when the two drugs were coadministered; however, in clinical drug interaction studies, aprepitant did not have clinically important effects on the pharmacokinetics of ondansetron. [30676] [31266] [34653] [40027] Aripiprazole: (Major) If ondansetron and aripiprazole must be coadministered, ECG monitoring is recommended. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of torsade de pointes (TdP). QT prolongation has occurred during therapeutic use of aripiprazole and following overdose. [31266] [32722] [42845] Arsenic Trioxide: (Major) Concomitant use of ondansetron and arsenic trioxide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28226] [28432] [28457] [31266] [32722] Artemether; Lumefantrine: (Major) Concomitant use of ondansetron and lumefantrine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [30855] [31266] [32722] [34653] [35401] Asenapine: (Major) Concomitant use of ondansetron and asenapine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [36343] Aspirin, ASA; Butalbital; Caffeine; Codeine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Aspirin, ASA; Carisoprodol; Codeine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Aspirin, ASA; Oxycodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering oxycodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43906] [44061] [49446] [60634] [61107] Atazanavir: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with atazanavir. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Atazanavir is an inhibitor of CYP3A4. Ondansetron is a CYP3A4 substrate. [28142] [34653] [40241] Atazanavir; Cobicistat: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with atazanavir. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Atazanavir is an inhibitor of CYP3A4. Ondansetron is a CYP3A4 substrate. [28142] [34653] [40241] (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Cobicistat is a strong inhibitor of CYP3A4 and an inhibitor of CYP2D6 and P-glycoprotein (P-gp) inhibitor. Ondansetron is a CYP3A4, CYP2D6, and P-gp substrate. [34653] [40241] [51664] [58000] Atomoxetine: (Major) Concomitant use of ondansetron and atomoxetine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [28405] [31266] Atropine; Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as methylene blue. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Azithromycin: (Major) Concomitant use of azithromycin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28855] [31266] [65170] Barbiturates: (Minor) Ondansetron elimination may be affected by cytochrome P-450 inducers. In a pharmacokinetic study of 16 patients with epilepsy who were maintained chronically on CYP3A4 inducers (e.g., barbiturates) a reduction in ondansetron AUC, Cmax, and half-life was observed, resulting in a significant increase in ondansetron clearance. However, these changes in ondansetron exposure are not thought to be clinically relevant; no dosage adjustment for ondansetron is recommended when CYP450 inducers are used concurrently. [22005] [31266] [55436] [57046] [57048] [57080] Bedaquiline: (Major) Concomitant use of ondansetron and bedaquiline increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [52746] [9564] Benzhydrocodone; Acetaminophen: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering benzhydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [49446] [62889] Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as methylene blue. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Bismuth Subcitrate Potassium; Metronidazole; Tetracycline: (Major) Concomitant use of metronidazole and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [36894] Bismuth Subsalicylate; Metronidazole; Tetracycline: (Major) Concomitant use of metronidazole and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [36894] Buprenorphine: (Major) Due to the potential for QT prolongation, cautious use and close monitoring are advisable if concurrent use of ondansetron and buprenorphine is necessary. Ondansetron may cause QT interval prolongation and a risk for torsade de pointes (TdP); buprenorphine caused QT prolongation in some patients during clinical trials. ECG monitoring is recommended if these drugs are used concurrently. In addition, concurrent use of opioids with other drugs that modulate serotonergic function, such as ondansetron, has resulted in serotonin syndrome in some cases. Patients should be carefully observed, particularly during treatment initiation and during dose adjustments. Discontinue the serotonergic medications if serotonin syndrome is suspected. [28548] [31266] [41453] [49444] [59321] [60270] [60833] [62649] Buprenorphine; Naloxone: (Major) Due to the potential for QT prolongation, cautious use and close monitoring are advisable if concurrent use of ondansetron and buprenorphine is necessary. Ondansetron may cause QT interval prolongation and a risk for torsade de pointes (TdP); buprenorphine caused QT prolongation in some patients during clinical trials. ECG monitoring is recommended if these drugs are used concurrently. In addition, concurrent use of opioids with other drugs that modulate serotonergic function, such as ondansetron, has resulted in serotonin syndrome in some cases. Patients should be carefully observed, particularly during treatment initiation and during dose adjustments. Discontinue the serotonergic medications if serotonin syndrome is suspected. [28548] [31266] [41453] [49444] [59321] [60270] [60833] [62649] Butalbital; Acetaminophen; Caffeine; Codeine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Cabotegravir; Rilpivirine: (Major) Concomitant use of rilpivirine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The degree of QT prolongation associated with rilpivirine is not clinically significant when administered within the recommended dosage range; QT prolongation has been described at 3 times the maximum recommended dose. [31266] [32722] [44376] Capsaicin; Metaxalone: (Moderate) Concomitant use of metaxalone and serotonin-receptor antagonists (5HT-3 receptor antagonists) may increase the risk for serotonin syndrome. Monitor patients for serotonin syndrome if concomitant use is necessary. [30830] Celecoxib; Tramadol: (Moderate) Monitor for opioid withdrawal and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant ondansetron and tramadol use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. Also, data from 2 small trials indicate that concomitant use of ondansetron may result in reduced analgesic activity of tramadol; patients receiving ondansetron used tramadol more frequently leading to an increased cumulative dose in patient-controlled administration of tramadol. [28314] [30857] [31266] Ceritinib: (Major) Concomitant use of ondansetron and ceritinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [57094] Chloroquine: (Major) Concomitant use of ondansetron and chloroquine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28229] [28230] [28231] [29758] [31266] [32722] [34335] [34353] [65157] [65170] Chlorpheniramine; Codeine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dihydrocodeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [30282] [31266] [31723] [49446] [58572] Chlorpheniramine; Hydrocodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Chlorpromazine: (Major) Concomitant use of ondansetron and chlorpromazine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28415] [28417] [31266] [32722] [43065] Ciprofloxacin: (Major) If ondansetron and ciprofloxacin must be coadministered, ECG monitoring is recommended. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of torsade de pointes (TdP). Additionally, rare cases of QT prolongation and torsade de pointes (TdP) have been reported with ciprofloxacin during postmarketing surveillance. Additionally ciprofloxacin inhibits the CYP1A2 isoenzyme, while ondansetron is metabolized by several isoenzymes, including CYP1A2. [28419] [28775] [29103] [31266] [40241] [43411] Cisapride: (Contraindicated) Avoid concomitant use of ondansetron and cisapride due to an increased risk for torsade de pointes (TdP) and QT/QTc prolongation. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [47221] Citalopram: (Major) Concomitant use of ondansetron and citalopram increases the risk of QT/QTc prolongation, torsade de pointes (TdP), and serotonin syndrome. Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. If concomitant use is necessary, consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, and monitor for serotonin syndrome. [28269] [31266] [32722] Clarithromycin: (Major) Concomitant use of ondansetron and clarithromycin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28225] [28238] [31266] [32722] Clofazimine: (Major) Concomitant use of clofazimine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [63936] Clozapine: (Major) Concomitant use of ondansetron and clozapine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28262] [31266] [32722] Cobicistat: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Cobicistat is a strong inhibitor of CYP3A4 and an inhibitor of CYP2D6 and P-glycoprotein (P-gp) inhibitor. Ondansetron is a CYP3A4, CYP2D6, and P-gp substrate. [34653] [40241] [51664] [58000] Codeine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Codeine; Guaifenesin: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Codeine; Guaifenesin; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Codeine; Phenylephrine; Promethazine: (Major) Concomitant use of ondansetron and promethazine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [55578] (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Codeine; Promethazine: (Major) Concomitant use of ondansetron and promethazine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [55578] (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [33654] [34883] [49446] Crizotinib: (Major) Concomitant use of ondansetron and crizotinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [34653] [45458] Daclatasvir: (Moderate) Systemic exposure of ondansetron, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with daclatasvir, a P-gp inhibitor. Taking these drugs together could increase or prolong the therapeutic effects of ondansetron; monitor patients for potential adverse effects. [31266] [34653] [60001] Darunavir: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4 and CYP2D6. Ondansetron is a CYP3A4 and CYP2D6, and substrate. [32432] [40241] Darunavir; Cobicistat: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Cobicistat is a strong inhibitor of CYP3A4 and an inhibitor of CYP2D6 and P-glycoprotein (P-gp) inhibitor. Ondansetron is a CYP3A4, CYP2D6, and P-gp substrate. [34653] [40241] [51664] [58000] (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4 and CYP2D6. Ondansetron is a CYP3A4 and CYP2D6, and substrate. [32432] [40241] Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Cobicistat is a strong inhibitor of CYP3A4 and an inhibitor of CYP2D6 and P-glycoprotein (P-gp) inhibitor. Ondansetron is a CYP3A4, CYP2D6, and P-gp substrate. [34653] [40241] [51664] [58000] (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with darunavir. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Darunavir is an inhibitor of CYP3A4 and CYP2D6. Ondansetron is a CYP3A4 and CYP2D6, and substrate. [32432] [40241] Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Caution and close monitoring are advised if these drugs are administered together. Ondansetron exposure may be altered resulting in increased adverse effects or decreased efficacy. Ondansetron is metabolized by the hepatic isoenzymes CYP3A4, CYP2D6, and CYP1A2; ritonavir inhibits CYP3A4 and CYP2D6 and induces CYP1A2. [31266] [47165] Dasatinib: (Major) Concomitant use of ondansetron and dasatinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [60087] Degarelix: (Major) Concomitant use of ondansetron and degarelix increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [46869] Desflurane: (Major) Concomitant use of ondansetron and halogenated anesthetics increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28457] [28458] [28754] [28755] [28756] [31266] [32722] Desvenlafaxine: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as desvenlafaxine. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Deutetrabenazine: (Major) If ondansetron and deutetrabenazine must be coadministered, ECG monitoring is recommended. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of torsade de pointes (TdP). Deutetrabenazine may prolong the QT interval, but the degree of QT prolongation is not clinically significant when deutetrabenazine is administered within the recommended dosage range. [31266] [61845] Dextromethorphan; Quinidine: (Contraindicated) Quinidine administration is associated with QT prolongation and torsades de pointes (TdP). Quinidine inhibits CYP2D6 and has QT-prolonging actions; quinidine is contraindicated with other drugs that prolong the QT interval and are metabolized by CYP2D6 as the effects on the QT interval may be increased during concurrent use of these agents. Drugs that prolong the QT and are substrates for CYP2D6 that are contraindicated with quinidine include ondansetron. [31266] [42280] [47357] Disopyramide: (Major) Concomitant use of ondansetron and disopyramide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [9564] Dofetilide: (Major) Concomitant use of ondansetron and dofetilide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28221] [31266] [32722] [59321] Dolasetron: (Major) These drugs would not be expected to be given together due to therapeutic class duplication; side effects, such as serotonergic actions, may be additive. Ondansetron has been associated with QT prolongation and post-marketing reports of torsade de pointes (TdP). If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. Dolasetron is associated with a lower, but possible risk for QT prolongation and TdP. [28308] [31266] Dolutegravir; Rilpivirine: (Major) Concomitant use of rilpivirine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The degree of QT prolongation associated with rilpivirine is not clinically significant when administered within the recommended dosage range; QT prolongation has been described at 3 times the maximum recommended dose. [31266] [32722] [44376] Donepezil: (Major) Concomitant use of ondansetron and donepezil increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [59321] [59322] Donepezil; Memantine: (Major) Concomitant use of ondansetron and donepezil increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [59321] [59322] Dronedarone: (Contraindicated) Concomitant use of dronedarone and ondansetron is contraindicated. Dronedarone is an inhibitor of CYP2D6, CYP3A, and P-gp. Ondansetron is a substrate for CYP2D6, CYP3A4, and P-gp. Coadministration of dronedarone and ondansetron may result in elevated plasma concentrations of ondansetron. In addition, ondansetron has been established to have a possible risk of QT prolongation and Torsade de Pointes (TdP). Dronedarone administration is associated with a dose-related increase in the QTc interval. The increase in QTc is approximately 10 milliseconds at doses of 400 mg twice daily (the FDA-approved dose) and up to 25 milliseconds at doses of 1600 mg twice daily. Although there are no studies examining the effects of dronedarone in patients receiving other QT prolonging drugs, coadministration of such drugs may result in additive QT prolongation. [31266] [36101] Droperidol: (Major) Concomitant use of ondansetron and droperidol increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28235] [28236] [28737] [31266] [32722] [51289] Duloxetine: (Moderate) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as duloxetine. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Efavirenz: (Major) Coadministration of efavirenz and ondansetron may increase the risk for QT prolongation and torsade de pointes (TdP). QT prolongation has been observed with use of efavirenz. Although data are limited, the manufacturer of efavirenz recommends an alternative antiretroviral be considered for patients receiving medications with a known risk for TdP. Ondansetron has been associated with QT prolongation and post-marketing reports of TdP. Risk for QT prolongation increases with increased dosage, and a 32 mg IV dose must no longer be used for prevention of chemotherapy induced emesis. If these drugs must be coadministered, ECG monitoring is recommended. In addition, efavirenz induces CYP3A4 and may decrease serum concentrations of drugs metabolized by this enzyme, such as ondansetron. [28001] [28442] [31266] Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Coadministration of efavirenz and ondansetron may increase the risk for QT prolongation and torsade de pointes (TdP). QT prolongation has been observed with use of efavirenz. Although data are limited, the manufacturer of efavirenz recommends an alternative antiretroviral be considered for patients receiving medications with a known risk for TdP. Ondansetron has been associated with QT prolongation and post-marketing reports of TdP. Risk for QT prolongation increases with increased dosage, and a 32 mg IV dose must no longer be used for prevention of chemotherapy induced emesis. If these drugs must be coadministered, ECG monitoring is recommended. In addition, efavirenz induces CYP3A4 and may decrease serum concentrations of drugs metabolized by this enzyme, such as ondansetron. [28001] [28442] [31266] Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Coadministration of efavirenz and ondansetron may increase the risk for QT prolongation and torsade de pointes (TdP). QT prolongation has been observed with use of efavirenz. Although data are limited, the manufacturer of efavirenz recommends an alternative antiretroviral be considered for patients receiving medications with a known risk for TdP. Ondansetron has been associated with QT prolongation and post-marketing reports of TdP. Risk for QT prolongation increases with increased dosage, and a 32 mg IV dose must no longer be used for prevention of chemotherapy induced emesis. If these drugs must be coadministered, ECG monitoring is recommended. In addition, efavirenz induces CYP3A4 and may decrease serum concentrations of drugs metabolized by this enzyme, such as ondansetron. [28001] [28442] [31266] Elbasvir; Grazoprevir: (Moderate) Administering ondansetron with elbasvir; grazoprevir may result in elevated ondansetron plasma concentrations. Ondansetron is a substrate of CYP3A; grazoprevir is a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of adverse events. [31266] [34653] [60523] Eliglustat: (Major) Coadminister ondansetron and eliglustat cautiously with close monitoring; there may be an increased risk of QT prolongation and/or ondansetron-associated adverse effects. Ondansetron dosage reduction may be considered, depending on the clinical situation. Eliglustat is a CYP2D6 and P-glycoprotein (P-gp) inhibitor that is predicted to cause PR, QRS, and/or QT prolongation at significantly elevated plasma concentrations. Although ondansetron is primarily metabolized by other CYP450 isoenzymes (i.e., CYP3A4 and CYP1A2), it is metabolized to a lesser extent by CYP2D6 and is considered a P-gp substrate. In addition, ondansetron has been associated with QT prolongation and post-marketing reports of torsade de pointes (TdP). [31266] [34653] [49444] [57803] Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Cobicistat is a strong inhibitor of CYP3A4 and an inhibitor of CYP2D6 and P-glycoprotein (P-gp) inhibitor. Ondansetron is a CYP3A4, CYP2D6, and P-gp substrate. [34653] [40241] [51664] [58000] Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) The plasma concentrations of ondansetron may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as GI or CNS effects, is recommended during coadministration. Cobicistat is a strong inhibitor of CYP3A4 and an inhibitor of CYP2D6 and P-glycoprotein (P-gp) inhibitor. Ondansetron is a CYP3A4, CYP2D6, and P-gp substrate. [34653] [40241] [51664] [58000] Emtricitabine; Rilpivirine; Tenofovir alafenamide: (Major) Concomitant use of rilpivirine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The degree of QT prolongation associated with rilpivirine is not clinically significant when administered within the recommended dosage range; QT prolongation has been described at 3 times the maximum recommended dose. [31266] [32722] [44376] Emtricitabine; Rilpivirine; Tenofovir Disoproxil Fumarate: (Major) Concomitant use of rilpivirine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The degree of QT prolongation associated with rilpivirine is not clinically significant when administered within the recommended dosage range; QT prolongation has been described at 3 times the maximum recommended dose. [31266] [32722] [44376] Encorafenib: (Major) Concomitant use of ondansetron and encorafenib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [63317] Entrectinib: (Major) Concomitant use of ondansetron and entrectinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [64567] Eribulin: (Major) Concomitant use of ondansetron and eribulin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [42449] Erythromycin: (Major) Concomitant use of ondansetron and erythromycin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [28251] [31266] Escitalopram: (Major) Concomitant use of ondansetron and escitalopram increases the risk of QT/QTc prolongation, torsade de pointes (TdP), and serotonin syndrome. Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. If concomitant use is necessary, consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, and monitor for serotonin syndrome. [28270] [31266] Etravirine: (Moderate) Etravirine is a CYP3A4 inducer/substrate and a P-glycoprotein (PGP) inhibitor and ondansetron is a CYP3A4 and PGP substrate. Caution is warranted if these drugs are coadministered. [11512] [33718] [7619] Fenfluramine: (Moderate) Monitor for decreased efficacy of fenfluramine if coadministered with serotonin receptor antagonists. Concurrent use may decrease the activity of fenfluramine. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [65634] Fentanyl: (Moderate) If concomitant use of fentanyl and ondansetron is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. [31266] [40944] Fingolimod: (Major) Concomitant use of ondansetron and fingolimod increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] Flecainide: (Major) Concomitant use of ondansetron and flecainide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [23774] [28752] [31266] Fluconazole: (Contraindicated) Concomitant administration of fluconazole and drugs that both prolong the QT interval and are CYP3A4 substrates is contraindicated according to the FDA-approved product labeling. The exact risk for QT prolongation when fluconazole and ondansetron are administered together has not been clearly defined. If ondansetron and fluconazole are administered together, extreme caution and careful monitoring is advised, especially if higher doses are used or if other drugs that may affect CYP1A2 or CYP2D6 are also given. Fluconazole is a CYP3A4 inhibitor. Ondansetron is metabolized by CYP3A, CYP1A2, and CYP2D6. In vivo microsomal inhibition data has suggested that no single isoenzyme dominates ondansetron's metabolism thereby making clinically significant interactions due to inhibition of a single isoenzyme unlikely; however, since the publication of this data, ondansetron has been found to produce concentration-dependent QT prolongation. It is not clear what degree of enzyme inhibition or increased concentration is required to increase the risk of QT prolongation. Inhibition of CYP3A isoenzymes is likely to increase with higher fluconazole doses (>= 200 mg/day in adults). [28674] [29036] [31266] [34447] [57433] [57434] Fluoxetine: (Major) Due to the potential for QT prolongation, cautious use and close monitoring are advisable if concurrent use of fluoxetine and ondansetron is necessary. Both medications may cause QT interval prolongation and a risk for torsade de pointes (TdP). ECG monitoring has been recommended for at-risk patients. In addition, concurrent use of ondansetron with other drugs that modulate serotonergic function, such as fluoxetine, has resulted in serotonin syndrome in some cases. Patients should be carefully observed, particularly during treatment initiation and during dose adjustments. Discontinue the serotonergic medications if serotonin syndrome is suspected. [31266] [32127] [49444] Fluphenazine: (Minor) If ondansetron and fluphenazine must be coadministered, ECG monitoring is recommended. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of torsade de pointes (TdP). Fluphenazine is associated with a possible risk for QT prolongation. Theoretically, fluphenazine may increase the risk of QT prolongation if coadministered with other drugs that have a risk of QT prolongation. [28415] [31266] [32722] Fluvoxamine: (Major) Concomitant use of fluvoxamine and ondansetron may increase the risk of serotonin syndrome, QT prolongation, and torsade de pointes (TdP). Cases of QT prolongation and TdP have been reported during postmarketing use of fluvoxamine. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of TdP. If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. In addition, both fluvoxamine and ondansetron have central serotonin enhancing effects; therefore, serotonin syndrome is possible. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome occurs, all serotonergic agents should be discontinued and appropriate medical treatment should be implemented. [31266] [50507] Fosamprenavir: (Moderate) Concomitant use of ondansetron and fosamprenavir may result in altered ondansetron plasma concentrations. Ondansetron is a substrate of the hepatic isoenzyme CYP3A4 and drug transporter P-glycoprotein (P-gp). Amprenavir, the active metabolite of fosamprenavir, is an inducer of P-gp and a potent inhibitor and moderate inducer of CYP3A4. [29012] [31266] [34653] Foscarnet: (Major) Concomitant use of ondansetron and foscarnet increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28377] [31266] Fosphenytoin: (Minor) Fosphenytoin may reduce the efficacy of ondansetron by decreasing its systemic exposure; however, based on available data, no ondansetron dosage adjustment is recommended. If used together, monitor patients for antiemetic efficacy. Fosphenytoin is a strong CYP3A inducer. Ondansetron is a substrate for CY1A2, CYP2D6, and CYP3A4, with CYP3A4 playing a predominant role in ondansetron turnover. During pharmacokinetic studies, patients treated with strong CYP3A inducers (i.e., phenytoin, carbamazepine, rifampin) and ondansetron had significantly increased ondansetron clearance, resulting in significant reductions in AUC, Cmax, and half-life. However, these changes in ondansetron exposure are not thought to be clinically relevant. [22005] [31266] [40241] [55436] [56579] [57046] [57048] [57080] [57105] Fostemsavir: (Major) Concomitant use of ondansetron and fostemsavir increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The degree of QT prolongation associated with fostemsavir is not clinically significant when administered within the recommended dosage range; QT prolongation has been described at 2 times the maximum recommended dose. [31266] [65666] Gemifloxacin: (Major) Concomitant use of ondansetron and gemifloxacin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28419] [28420] [28424] [31266] [9564] Gemtuzumab Ozogamicin: (Major) Concomitant use of ondansetron and gemtuzumab ozogamicin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [62292] Gilteritinib: (Major) Concomitant use of ondansetron and gilteritinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [63787] Glasdegib: (Major) Concomitant use of ondansetron and glasdegib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [63777] Glecaprevir; Pibrentasvir: (Moderate) Caution is advised with the coadministration of glecaprevir and ondansetron as coadministration may increase serum concentrations of ondansetron and increase the risk of adverse effects. Ondansetron is a substrate of P-glycoprotein (P-gp); glecaprevir is a P-gp inhibitor. [31266] [34653] [62201] (Moderate) Caution is advised with the coadministration of pibrentasvir and ondansetron as coadministration may increase serum concentrations of ondansetron and increase the risk of adverse effects. Ondansetron is a substrate of P-glycoprotein (P-gp); pibrentasvir is a P-gp inhibitor. [31266] [34653] [62201] Goserelin: (Major) Concomitant use of ondansetron and goserelin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28592] [31266] Granisetron: (Major) Granisetron has been associated with QT prolongation. According to the manufacturer, use of granisetron in patients concurrently treated with drugs known to prolong the QT interval and/or are arrhythmogenic, may result in clinical consequences. Drugs with a possible risk for QT prolongation and torsade de pointes (TdP) that should be used cautiously and with close monitoring with granisetron include ondansetron. The two drugs are from the same therapeutic class, and would not be expected to be prescribed together. Serotonergic actions of the two drugs might also increase the risk for additive serotonergic side effects. [31266] [31723] Guaifenesin; Hydrocodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Guaifenesin; Hydrocodone; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Halogenated Anesthetics: (Major) Concomitant use of ondansetron and halogenated anesthetics increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28457] [28458] [28754] [28755] [28756] [31266] [32722] Haloperidol: (Major) Concomitant use of ondansetron and haloperidol increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The intravenous route may carry a higher risk for haloperidol-induced QT/QTc prolongation than other routes of administration. [23500] [23779] [28225] [28307] [28415] [28416] [31266] [32722] Histrelin: (Major) Concomitant use of ondansetron and histrelin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [30369] [31266] Homatropine; Hydrocodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Hydrocodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Hydrocodone; Ibuprofen: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Hydrocodone; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydrocodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43291] [49446] [56303] Hydromorphone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering hydromorphone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [39635] [49446] [49619] Hydroxychloroquine: (Major) Concomitant use of hydroxychloroquine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [41806] [65170] Hydroxyzine: (Major) Concomitant use of ondansetron and hydroxyzine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [47129] Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as methylene blue. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Ibuprofen; Oxycodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering oxycodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43906] [44061] [49446] [60634] [61107] Ibutilide: (Major) Concomitant use of ondansetron and ibutilide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [41830] [9564] Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with ondansetron, a CYP3A substrate, as ondansetron toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib. [57675] [7619] Iloperidone: (Major) Concomitant use of ondansetron and iloperidone increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [36146] [9564] Inotuzumab Ozogamicin: (Major) Concomitant use of ondansetron and inotuzumab increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [62245] Ipecac: (Major) Ipecac has been shown to be effective in producing emesis in patients who have ingested antiemetics, provided ipecac is given promptly (usually within 1 hour of antiemetic consumption). If ipecac is administered after the antiemetic therapy has begun to exert therapeutic effects, ipecac may be less effective. The duration of the antiemetics action may need to be taken into account when selecting the appropriate clinical path for treating patients for overdosage. Patients on chronic or longer-acting antiemetic therapy, such as the 5HT-3 receptor antagonists, may be unresponsive to ipecac or other methods which induce vomiting. [6742] Isavuconazonium: (Moderate) Concomitant use of isavuconazonium with ondansetron may result in increased serum concentrations of ondansetron. Ondansetron is a substrate of the hepatic isoenzyme CYP3A4 and drug transporter P-glycoprotein (P-gp); isavuconazole, the active moiety of isavuconazonium is an inhibitor of CYP3A4 and P-gp. Caution and close monitoring are advised if these drugs are used together. [31266] [34653] [59042] Isocarboxazid: (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant monoamine oxidase inhibitor (MAOI) and ondansetron use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. [27957] [29656] [31266] [53440] Isoflurane: (Major) Concomitant use of ondansetron and halogenated anesthetics increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28457] [28458] [28754] [28755] [28756] [31266] [32722] Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Minor) Rifampin may reduce the efficacy of ondansetron by decreasing its systemic exposure; however, based on available data, no ondansetron dosage adjustment is recommended. If used together, monitor patients for antiemetic efficacy. In a pharmacokinetic study of 10 healthy subjects receiving a single-dose intravenous dose of ondansetron 8 mg after 600 mg rifampin once daily for 5 days, the AUC and the half-life of ondansetron were reduced by 48% and 46%, respectively. The proposed mechanism is rifampin-related induction of ondansetron metabolism through cytochrome P450 3A4. These changes in ondansetron exposure with CYP3A4 inducers are not thought to be clinically relevant. [26045] [31266] Isoniazid, INH; Rifampin: (Minor) Rifampin may reduce the efficacy of ondansetron by decreasing its systemic exposure; however, based on available data, no ondansetron dosage adjustment is recommended. If used together, monitor patients for antiemetic efficacy. In a pharmacokinetic study of 10 healthy subjects receiving a single-dose intravenous dose of ondansetron 8 mg after 600 mg rifampin once daily for 5 days, the AUC and the half-life of ondansetron were reduced by 48% and 46%, respectively. The proposed mechanism is rifampin-related induction of ondansetron metabolism through cytochrome P450 3A4. These changes in ondansetron exposure with CYP3A4 inducers are not thought to be clinically relevant. [26045] [31266] Itraconazole: (Major) Caution is advised when administering itraconazole with drugs that are known to prolong that QT interval and are metabolized by CYP3A4, such as ondansetron. Both ondansetron and itraconazole are associated with QT prolongation; coadministration may increase this risk. If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. In addition, coadministration of itraconazole (a potent CYP3A4 inhibitor) with ondansetron (a CYP3A4 substrate) may result in elevated ondansetron plasma concentrations and an increased risk for adverse events, including QT prolongation. If itraconazole therapy is stopped, it may be prudent to continue close monitoring for up to 2 weeks after discontinuing itraconazole. Once discontinued, the plasma concentration of itraconazole decreases to almost undetectable concentrations within 7 to 14 days. The decline in plasma concentrations may be even more gradual in patients with hepatic cirrhosis or who are receiving concurrent CYP3A4 inhibitors. [29036] [31266] [40233] [57441] [57486] Ivosidenib: (Major) Concomitant use of ondansetron and ivosidenib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [63368] Ketoconazole: (Contraindicated) Avoid concomitant use of ketoconazole and ondansetron due to an increased risk for torsade de pointes (TdP) and QT/QTc prolongation. Ketoconazole is associated with an established risk for QT prolongation and TdP. Electrocardiogram (ECG) monitoring is recommended in patients at risk if use together cannot be avoided and is medically necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [27982] [31266] [49444] [67231] Lansoprazole; Amoxicillin; Clarithromycin: (Major) Concomitant use of ondansetron and clarithromycin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28225] [28238] [31266] [32722] Lapatinib: (Major) Concomitant use of ondansetron and lapatinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [33192] Lasmiditan: (Moderate) Serotonin syndrome may occur during coadministration of lasmiditan and serotonin-receptor antagonists. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly after a dose increase or the addition of other serotonergic medications to an existing regimen. Discontinue all serotonergic agents if serotonin syndrome occurs and implement appropriate medical management. [28308] [49444] [49815] [61077] [64685] Ledipasvir; Sofosbuvir: (Moderate) Caution and close monitoring of ondansetron-associated adverse reactions is advised with concomitant administration of ledipasvir. Ondansetron is a substrate of the drug transporter P-glycoprotein (P-gp); ledipasvir is a P-gp inhibitor. Taking these drugs together may increase ondansetron plasma concentrations. [31266] [34653] [58167] Lefamulin: (Major) Concomitant use of ondansetron and lefamulin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [64576] Lenvatinib: (Major) Concomitant use of ondansetron and lenvatinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [58782] Leuprolide: (Major) Concomitant use of ondansetron and leuprolide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [43800] Leuprolide; Norethindrone: (Major) Concomitant use of ondansetron and leuprolide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [43800] Levofloxacin: (Major) Concomitant use of ondansetron and levofloxacin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [28421] [31266] Levoketoconazole: (Contraindicated) Avoid concomitant use of ketoconazole and ondansetron due to an increased risk for torsade de pointes (TdP) and QT/QTc prolongation. Ketoconazole is associated with an established risk for QT prolongation and TdP. Electrocardiogram (ECG) monitoring is recommended in patients at risk if use together cannot be avoided and is medically necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [27982] [31266] [49444] [67231] Levomilnacipran: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as levomilnacipran. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Levorphanol: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering levorphanol with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [49446] [60958] Linezolid: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as linezolid. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [28599] [31266] Lithium: (Major) Due to the potential for QT prolongation, cautious use and close monitoring are advisable if concurrent use of lithium and ondansetron is necessary. Both medications may cause QT interval prolongation and a risk for torsade de pointes (TdP). ECG monitoring has been recommended for at-risk patients. In addition, concurrent use of ondansetron with other drugs that modulate serotonergic function, such as lithium, has resulted in serotonin syndrome in some cases. Patients should be carefully observed, particularly during treatment initiation and during dose adjustments. Discontinue the serotonergic medications if serotonin syndrome is suspected. [31266] [49444] [59809] [59810] [59811] (Moderate) Moderate to significant dietary sodium changes, or changes in sodium and fluid intake, may affect lithium excretion. Systemic sodium chloride administration may result in increased lithium excretion and therefore, decreased serum lithium concentrations. In addition, high fluid intake may increase lithium excretion. For patients receiving sodium-containing intravenous fluids, symptom control and lithium concentrations should be carefully monitored. It is recommended that patients taking lithium maintain consistent dietary sodium consumption and adequate fluid intake during the initial stabilization period and throughout lithium treatment. Supplemental oral sodium and fluid should be only be administered under careful medical supervision. [28654] [55943] Lofexidine: (Major) Concomitant use of ondansetron and lofexidine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [63161] Loperamide: (Major) Concomitant use of ondansetron and loperamide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [30106] [31266] [60864] Loperamide; Simethicone: (Major) Concomitant use of ondansetron and loperamide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [30106] [31266] [60864] Lopinavir; Ritonavir: (Major) Concomitant use of ondansetron and lopinavir increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28341] [31266] [65157] [65170] (Moderate) Caution and close monitoring are advised if these drugs are administered together. Ondansetron exposure may be altered resulting in increased adverse effects or decreased efficacy. Ondansetron is metabolized by the hepatic isoenzymes CYP3A4, CYP2D6, and CYP1A2; ritonavir inhibits CYP3A4 and CYP2D6 and induces CYP1A2. [31266] [47165] Lumacaftor; Ivacaftor: (Minor) Lumacaftor; ivacaftor may reduce the efficacy of ondansetron by decreasing its systemic exposure; however, based on available data, no ondansetron dosage adjustment is recommended. If used together, monitor patients for antiemetic efficacy. Lumacaftor is a strong CYP3A inducer. Ondansetron is a substrate for CY1A2, CYP2D6, and CYP3A4, with CYP3A4 playing a predominant role in ondansetron turnover. During pharmacokinetic studies, patients treated with strong CYP3A inducers (i.e., phenytoin, carbamazepine, rifampin) and ondansetron had significantly increased ondansetron clearance, resulting in significant reductions in AUC, Cmax, and half-life. However, these changes in ondansetron exposure are not thought to be clinically relevant. [31266] [49444] [59891] Macimorelin: (Major) Concomitant use of ondansetron and macimorelin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [62723] Maprotiline: (Major) Concomitant use of ondansetron and maprotiline increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28759] [31266] [32722] Mefloquine: (Major) Concomitant use of ondansetron and mefloquine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28301] [31266] [32722] Meperidine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering meperidine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [30988] [31266] [31723] [49446] [51182] Meperidine; Promethazine: (Major) Concomitant use of ondansetron and promethazine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [55578] (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering meperidine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [30988] [31266] [31723] [49446] [51182] Metaxalone: (Moderate) Concomitant use of metaxalone and serotonin-receptor antagonists (5HT-3 receptor antagonists) may increase the risk for serotonin syndrome. Monitor patients for serotonin syndrome if concomitant use is necessary. [30830] Methadone: (Major) Concomitant use of ondansetron and methadone increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28319] [28320] [28321] [28322] [28379] [31266] [32722] [33136] Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as methylene blue. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Methylene Blue: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as methylene blue. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] Metronidazole: (Major) Concomitant use of metronidazole and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [36894] Midostaurin: (Major) Concomitant use of ondansetron and midostaurin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [61906] Mifepristone: (Major) Concomitant use of ondansetron and mifepristone increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [48697] Mirabegron: (Moderate) Mirabegron is a moderate CYP2D6 inhibitor. Exposure of drugs partially metabolized by CYP2D6, such as ondansetron may be increased when co-administered with mirabegron. Therefore, appropriate monitoring and dose adjustment may be necessary. [31266] [34653] [51111] Mirtazapine: (Major) Due to the potential for QT prolongation, cautious use and close monitoring are advisable if concurrent use of mirtazapine and ondansetron is necessary. Both medications may cause QT interval prolongation and a risk for torsade de pointes (TdP). ECG monitoring has been recommended for at-risk patients. In addition, concurrent use of ondansetron with other drugs that modulate serotonergic function, such as mirtazapine, has resulted in serotonin syndrome in some cases. Patients should be carefully observed, particularly during treatment initiation and during dose adjustments. Discontinue the serotonergic medications if serotonin syndrome is suspected. [31266] [40942] [49444] Mitotane: (Minor) Use caution if mitotane and ondansetron are used concomitantly, and monitor for decreased efficacy of ondansetron and a possible change in dosage requirements. Mitotane is a strong CYP3A4 inducer and ondansetron is a CYP3A4 substrate; coadministration may result in decreased plasma concentrations of ondansetron. During pharmacokinetic studies, patients treated with strong CYP3A inducers (i.e., phenytoin, carbamazepine, rifampin) and ondansetron had significantly increased ondansetron clearance, resulting in significant reductions in AUC, Cmax, and half-life. However, these changes in ondansetron exposure are not thought to be clinically relevant. [31266] [34653] [41934] Mobocertinib: (Major) Concomitant use of ondansetron and mobocertinib increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [66990] Monoamine oxidase inhibitors: (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant monoamine oxidase inhibitor (MAOI) and ondansetron use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. [27957] [29656] [31266] [53440] Morphine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering morphine with serotonin-receptor antagonist. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [40951] [46350] [49446] [64690] Morphine; Naltrexone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering morphine with serotonin-receptor antagonist. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [40951] [46350] [49446] [64690] Moxifloxacin: (Major) Concomitant use of ondansetron and moxifloxacin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28423] [31266] [9564] Nalbuphine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering nalbuphine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [49446] [49631] Nilotinib: (Major) Avoid coadministration of nilotinib with ondansetron due to an increased risk for QT prolongation and torsade de pointes (TdP). Systemic exposure of ondansetron may also be increased resulting in an increase in ondansetron-related adverse reactions. Nilotinib is a moderate CYP3A4 inhibitor; sudden death and QT interval prolongation have occurred in patients who received nilotinib therapy. Ondansetron is a CYP3A4 substrate that has also been associated with a dose-related increase in the QT interval and postmarketing reports of TdP. [33557] [40241] Nirmatrelvir; Ritonavir: (Moderate) Caution and close monitoring are advised if these drugs are administered together. Ondansetron exposure may be altered resulting in increased adverse effects or decreased efficacy. Ondansetron is metabolized by the hepatic isoenzymes CYP3A4, CYP2D6, and CYP1A2; ritonavir inhibits CYP3A4 and CYP2D6 and induces CYP1A2. [31266] [47165] Octreotide: (Major) Concomitant use of ondansetron and octreotide increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. Octreotide has a limited effect on the QT/QTc interval at therapeutic doses but may cause bradycardia and other conduction disturbances which may increase the risk for TdP in patients with a prolonged QT/QTc interval. [28432] [29113] [30624] [31266] [32722] Ofloxacin: (Major) Concomitant use of ondansetron and ofloxacin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [29833] [30738] [31266] [48869] Olanzapine: (Major) Concomitant use of ondansetron and olanzapine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28785] [31266] [32722] [32732] [32734] [32745] [32746] Olanzapine; Fluoxetine: (Major) Concomitant use of ondansetron and olanzapine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28785] [31266] [32722] [32732] [32734] [32745] [32746] (Major) Due to the potential for QT prolongation, cautious use and close monitoring are advisable if concurrent use of fluoxetine and ondansetron is necessary. Both medications may cause QT interval prolongation and a risk for torsade de pointes (TdP). ECG monitoring has been recommended for at-risk patients. In addition, concurrent use of ondansetron with other drugs that modulate serotonergic function, such as fluoxetine, has resulted in serotonin syndrome in some cases. Patients should be carefully observed, particularly during treatment initiation and during dose adjustments. Discontinue the serotonergic medications if serotonin syndrome is suspected. [31266] [32127] [49444] Olanzapine; Samidorphan: (Major) Concomitant use of ondansetron and olanzapine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28785] [31266] [32722] [32732] [32734] [32745] [32746] Oliceridine: (Moderate) If concomitant use of oliceridine and serotonin-receptor antagonists is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. [28445] [28583] [29121] [29266] [29267] [31864] [31869] [65809] Ombitasvir; Paritaprevir; Ritonavir: (Moderate) Caution and close monitoring are advised if these drugs are administered together. Ondansetron exposure may be altered resulting in increased adverse effects or decreased efficacy. Ondansetron is metabolized by the hepatic isoenzymes CYP3A4, CYP2D6, and CYP1A2; ritonavir inhibits CYP3A4 and CYP2D6 and induces CYP1A2. [31266] [47165] Omeprazole; Amoxicillin; Rifabutin: (Minor) Monitor for altered response to ondansetron during coadministration of rifabutin. Rifabutin may increase the clearance and decrease blood concentrations of ondansetron. However, no dosage adjustment for ondansetron is recommended during coadministration. [26045] Oritavancin: (Minor) Ondansetron is metabolized by CYP3A4 and CYP2D6; oritavancin is a weak CYP3A4 and CYP2D6 inducer. Plasma concentrations and efficacy of ondansetron may be reduced if these drugs are administered concurrently. [31266] [57741] Osilodrostat: (Major) Concomitant use of osilodrostat and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [65098] Osimertinib: (Major) Concomitant use of osimertinib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [60297] Oxaliplatin: (Major) Concomitant use of oxaliplatin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [41958] Oxycodone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering oxycodone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [43906] [44061] [49446] [60634] [61107] Oxymorphone: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering oxymorphone with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [32438] [42029] [49446] Ozanimod: (Major) In general, do not initiate ozanimod in patients taking ondansetron due to the risk of additive bradycardia, QT prolongation, and torsade de pointes (TdP). Additionally, there is a potential for hypertensive crisis. If concomitant use is necessary, monitor ECGs and for hypertension. An active metabolite of ozanimod inhibits MAO-B, which may increase the potential for hypertensive crisis. Ozanimod may also result in a transient decrease in heart rate and atrioventricular conduction delays. Ozanimod has not been studied in patients taking concurrent QT prolonging drugs; however, QT prolonging drugs have been associated with TdP in patients with bradycardia. Ondansetron is a serotonergic drug that has been associated with a dose-related increase in the QT interval and postmarketing reports of TdP. [31266] [65169] Pacritinib: (Major) Concomitant use of pacritinib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [67427] Paliperidone: (Major) Concomitant use of paliperidone and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [40936] Panobinostat: (Major) The co-administration of panobinostat with antiemetic agents such as ondansetron may increase the risk of QT prolongation. If concomitant use cannot be avoided, obtain electrocardiograms frequently and closely monitor patients for signs and symptoms of ondansetron toxicity, including QT prolongation and cardiac arrhythmias. Panobinostat is a CYP2D6 inhibitor and ondansetron is a CYP2D6 substrate. When a single-dose of a CYP2D6-sensitive substrate was administered after 3 doses of panobinostat (20 mg given on days 3, 5, and 8), the CYP2D6 substrate Cmax increased by 20% to 200% and the AUC value increased by 20% to 130% in 14 patients with advanced cancer; exposure was highly variable (coefficient of variance > 150%). [31266] [58821] Paroxetine: (Major) Concomitant use of ondansetron and paroxetine increases the risk for serotonin syndrome. Avoid concomitant use if possible and monitor for serotonin syndrome if use is necessary. [28260] [31266] [59321] Pasireotide: (Major) Concomitant use of pasireotide and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [52611] Pazopanib: (Major) Concomitant use of pazopanib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [37098] Pentamidine: (Major) Concomitant use of pentamidine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [23620] [23778] [28419] [28879] [31266] [9564] Perphenazine: (Minor) Due to a possible risk for QT prolongation and torsade de pointes (TdP), ondansetron and perphenazine should be used together cautiously. Ondansetron has been associated with QT prolongation and post-marketing reports of torsade de pointes (TdP). Among 42 patients receiving a 4 mg bolus dose of intravenous ondansetron for the treatment of postoperative nausea and vomiting, the mean maximal QTc interval prolongation was 20 +/- 13 msec at the third minute after antiemetic administration (p < 0.0001). If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. Perphenazine, a phenothiazine, is associated with a possible risk for QT prolongation. [28415] [31266] [9564] Perphenazine; Amitriptyline: (Minor) Due to a possible risk for QT prolongation and torsade de pointes (TdP), ondansetron and perphenazine should be used together cautiously. Ondansetron has been associated with QT prolongation and post-marketing reports of torsade de pointes (TdP). Among 42 patients receiving a 4 mg bolus dose of intravenous ondansetron for the treatment of postoperative nausea and vomiting, the mean maximal QTc interval prolongation was 20 +/- 13 msec at the third minute after antiemetic administration (p < 0.0001). If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. Perphenazine, a phenothiazine, is associated with a possible risk for QT prolongation. [28415] [31266] [9564] Phenelzine: (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant monoamine oxidase inhibitor (MAOI) and ondansetron use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. [27957] [29656] [31266] [53440] Phenytoin: (Minor) Phenytoin may reduce the efficacy of ondansetron by decreasing its systemic exposure; however, based on available data, no ondansetron dosage adjustment is recommended. If used together, monitor patients for antiemetic efficacy. Phenytoin is a strong CYP3A inducer. Ondansetron is a substrate for CY1A2, CYP2D6, and CYP3A4, with CYP3A4 playing a predominant role in ondansetron turnover. During pharmacokinetic studies, patients treated with strong CYP3A inducers (i.e., phenytoin, carbamazepine, rifampin) and ondansetron had significantly increased ondansetron clearance, resulting in significant reductions in AUC, Cmax, and half-life. However, these changes in ondansetron exposure are not thought to be clinically relevant. [22005] [31266] [40241] [55436] [56579] [57046] [57048] [57080] [57105] Pimavanserin: (Major) Concomitant use of pimavanserin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [60748] Pimozide: (Contraindicated) Avoid concomitant use of pimozide and ondansetron due to an increased risk for torsade de pointes (TdP) and QT/QTc prolongation. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28225] [31266] [43463] Pitolisant: (Major) Concomitant use of pitolisant and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [64562] Ponesimod: (Major) In general, do not initiate ponesimod in patients taking ondansetron due to the risk of additive bradycardia, QT prolongation, and torsade de pointes (TdP). If treatment initiation is considered, seek advice from a cardiologist. Ponesimod initiation may result in a transient decrease in heart rate and atrioventricular conduction delays. Ponesimod has not been studied in patients taking concurrent QT prolonging drugs; however, QT prolonging drugs have been associated with TdP in patients with bradycardia. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of TdP. [31266] [66527] Posaconazole: (Contraindicated) Concomitant administration of posaconazole and drugs that both prolong the QT interval and are CYP3A4 substrates is contraindicated according to the FDA-approved product labeling. The exact risk for QT prolongation when posaconazole and ondansetron are administered together has not been clearly defined. If ondansetron and posaconazole are administered together, extreme caution and careful monitoring is advised, especially if higher doses are used or if other drugs that may affect CYP1A2 or CYP2D6 are also given. Posaconazole is a strong CYP3A4 inhibitor. Ondansetron is metabolized by CYP3A, CYP1A2, and CYP2D6. In vivo microsomal inhibition data has suggested that no single isoenzyme dominates ondansetron's metabolism thereby making clinically significant interactions due to inhibition of a single isoenzyme unlikely; however, since the publication of this data, ondansetron has been found to produce concentration-dependent QT prolongation. It is not clear what degree of enzyme inhibition or increased concentration is required to increase the risk of QT prolongation. [31266] [32723] [57433] [57434] Primaquine: (Major) Concomitant use of primaquine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [41984] Procainamide: (Major) Concomitant use of procainamide and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28250] [31266] Prochlorperazine: (Minor) Due to a possible risk for QT prolongation and torsade de pointes (TdP), ondansetron and prochlorperazine should be used together cautiously. Ondansetron has been associated with QT prolongation and post-marketing reports of torsade de pointes (TdP). Among 42 patients receiving a 4 mg bolus dose of intravenous ondansetron for the treatment of postoperative nausea and vomiting, the mean maximal QTc interval prolongation was 20 +/- 13 msec at the third minute after antiemetic administration (p < 0.0001). If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. Phenothiazines have been reported to prolong the QT interval. If coadministration is considered necessary, and the patient has known risk factors for cardiac disease or arrhythmia, then close monitoring is essential. [28225] [28415] [31266] [9564] Promethazine: (Major) Concomitant use of ondansetron and promethazine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [55578] Promethazine; Dextromethorphan: (Major) Concomitant use of ondansetron and promethazine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [55578] Promethazine; Phenylephrine: (Major) Concomitant use of ondansetron and promethazine increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [55578] Propafenone: (Major) Concomitant use of ondansetron and propafenone increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [28287] [31266] Quetiapine: (Major) Avoid coadministration of ondansetron and quetiapine due to the risk of QT prolongation. Monitor ECG for evidence of QT prolongation if concurrent use cannot be avoided. Limited data, including some case reports, suggest that quetiapine may be associated with a significant prolongation of the QTc interval in rare instances. Ondansetron has been associated with a dose-related increase in the QT interval and postmarketing reports of torsade de pointes (TdP). [29118] [31266] [32722] [33068] [33072] [33074] Quinidine: (Contraindicated) Quinidine administration is associated with QT prolongation and torsades de pointes (TdP). Quinidine inhibits CYP2D6 and has QT-prolonging actions; quinidine is contraindicated with other drugs that prolong the QT interval and are metabolized by CYP2D6 as the effects on the QT interval may be increased during concurrent use of these agents. Drugs that prolong the QT and are substrates for CYP2D6 that are contraindicated with quinidine include ondansetron. [31266] [42280] [47357] Quinine: (Major) Concurrent use of quinine and ondansetron should be avoided due to an increased risk for QT prolongation and torsade de pointes (TdP). Both drugs have been associated with prolongation of the QT interval and rare cases of TdP. In addition, concentrations of ondansetron may be increased with concomitant use of quinine. Ondansetron is a CYP3A4 and CYP2D6 substrate and quinine is an inhibitor of both enzymes. [31266] [31403] Ranolazine: (Major) Due to a possible risk for QT prolongation and torsade de pointes (TdP), ondansetron and ranolazine should be used together cautiously. Ondansetron has been associated with QT prolongation and post-marketing reports of torsade de pointes (TdP). Among 42 patients receiving a 4 mg bolus dose of intravenous ondansetron for the treatment of postoperative nausea and vomiting, the mean maximal QTc interval prolongation was 20 +/- 13 msec at the third minute after antiemetic administration (p < 0.0001). If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. Ranolazine is associated with dose- and plasma concentration-related increases in the QTc interval. The mean increase in QTc is about 6 milliseconds, measured at the tmax of the maximum dosage (1000 mg PO twice daily). However, in 5% of the population studied, increases in the QTc of at least 15 milliseconds have been reported. Although there are no studies examining the effects of ranolazine in patients receiving other QT prolonging drugs, coadministration of such drugs may result in additive QT prolongation. In addition, ondansetron is a substrate for CYP3A4 and CYP2D6 and P-glycoprotein (P-gp). Ranolazine is an inhibitor of CYP3A4 and CYP2D6 and P-gp. Concurrent administration of ranolazine and ondansetron may result in increased ondansetron concentrations. [31266] [31938] [9564] Relugolix: (Major) Concomitant use of relugolix and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [66183] Relugolix; Estradiol; Norethindrone acetate: (Major) Concomitant use of relugolix and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [66183] Remifentanil: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering remifentanil with serotonin-receptor antagonists. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [28897] [31266] [31723] [49446] Ribociclib: (Major) Avoid coadministration of ribociclib with ondansetron due to an increased risk for QT prolongation and torsade de pointes (TdP). Systemic exposure of ondansetron may also be increased resulting in an increase in ondansetron-related adverse reactions. Ribociclib is a strong CYP3A4 inhibitor that has been shown to prolong the QT interval in a concentration-dependent manner. Ondansetron is a CYP3A4 substrate that has also been associated with a dose-related increase in the QT interval and postmarketing reports of TdP. Concomitant use may increase the risk for QT prolongation. [31266] [34653] [61816] Ribociclib; Letrozole: (Major) Avoid coadministration of ribociclib with ondansetron due to an increased risk for QT prolongation and torsade de pointes (TdP). Systemic exposure of ondansetron may also be increased resulting in an increase in ondansetron-related adverse reactions. Ribociclib is a strong CYP3A4 inhibitor that has been shown to prolong the QT interval in a concentration-dependent manner. Ondansetron is a CYP3A4 substrate that has also been associated with a dose-related increase in the QT interval and postmarketing reports of TdP. Concomitant use may increase the risk for QT prolongation. [31266] [34653] [61816] Rifabutin: (Minor) Monitor for altered response to ondansetron during coadministration of rifabutin. Rifabutin may increase the clearance and decrease blood concentrations of ondansetron. However, no dosage adjustment for ondansetron is recommended during coadministration. [26045] Rifampin: (Minor) Rifampin may reduce the efficacy of ondansetron by decreasing its systemic exposure; however, based on available data, no ondansetron dosage adjustment is recommended. If used together, monitor patients for antiemetic efficacy. In a pharmacokinetic study of 10 healthy subjects receiving a single-dose intravenous dose of ondansetron 8 mg after 600 mg rifampin once daily for 5 days, the AUC and the half-life of ondansetron were reduced by 48% and 46%, respectively. The proposed mechanism is rifampin-related induction of ondansetron metabolism through cytochrome P450 3A4. These changes in ondansetron exposure with CYP3A4 inducers are not thought to be clinically relevant. [26045] [31266] Rilpivirine: (Major) Concomitant use of rilpivirine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The degree of QT prolongation associated with rilpivirine is not clinically significant when administered within the recommended dosage range; QT prolongation has been described at 3 times the maximum recommended dose. [31266] [32722] [44376] Risperidone: (Major) Concomitant use of risperidone and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28225] [28414] [28416] [31266] [32722] Ritonavir: (Moderate) Caution and close monitoring are advised if these drugs are administered together. Ondansetron exposure may be altered resulting in increased adverse effects or decreased efficacy. Ondansetron is metabolized by the hepatic isoenzymes CYP3A4, CYP2D6, and CYP1A2; ritonavir inhibits CYP3A4 and CYP2D6 and induces CYP1A2. [31266] [47165] Rolapitant: (Major) Use caution if ondansetron and rolapitant are used concurrently, and monitor for ondansetron-related adverse effects. Ondansetron is a substrate of CYP2D6 and P-glycoprotein (P-gp) and rolapitant is an inhibitor of CYP2D6 and P-gp. The inhibitory effect of rolapitant is expected to persist beyond 28 days for an unknown duration. Exposure to another CYP2D6 substrate, following a single dose of rolapitant increased about 3-fold on Days 8 and Day 22. The inhibition of CYP2D6 persisted on Day 28 with a 2.3-fold increase in the CYP2D6 substrate concentrations, the last time point measured. When oral rolapitant was administered with another P-gp substrate, the day 1 Cmax and AUC were increased by 70% and 30%, respectively; the Cmax and AUC on day 8 were not studied. When the P-gp substrate was administered with a single dose of intravenous rolapitant, no effect on AUC and a 21% increase in the Cmax of P-gp substrate was observed. [40241] [60142] Romidepsin: (Major) Concomitant use of romidepsin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [37292] Saquinavir: (Major) Concurrent use of saquinavir boosted with ritonavir and ondansetron should be avoided if possible due to the risk of life threatening arrhythmias such as torsade de pointes (TdP). Saquinavir boosted with ritonavir is a potent inhibitor of CYP3A4, an isoenzyme responsible for the metabolism of ondansetron. Further, both saquinavir and ondansetron are substrates of P-glycoprotein, which when administered together may increase the absorption or decrease the clearance of the other drug. This complex interaction may ultimately result in altered plasma concentrations of both ondansetron and saquinavir. Additionally, saquinavir boosted with ritonavir causes dose-dependent QT and PR prolongation; if possible, avoid use with other drugs that may prolong the QT or PR interval, such as ondansetron. If no alternative therapy is acceptable, perform a baseline ECG prior to initiation of concomitant therapy and follow recommended ECG monitoring. [11416] [11417] [11512] [28995] [31266] [39156] [40241] Selegiline: (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant selegiline and serotonin-receptor antagonist use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. [28308] [32026] [32436] [49444] [49815] Selpercatinib: (Major) Concomitant use of selpercatinib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [65387] Sertraline: (Major) Due to the potential for QT prolongation, cautious use and close monitoring are advisable if concurrent use of sertraline and ondansetron is necessary. Both medications may cause QT interval prolongation. The risk of sertraline-induced QT prolongation is generally considered to be low in clinical practice. Its effect on QTc interval is minimal (typically less than 5 msec), and the drug has been used safely in patients with cardiac disease. ECG monitoring has been recommended for at-risk patients. In addition, concurrent use of ondansetron with other drugs that modulate serotonergic function, such as SSRIs, has resulted in serotonin syndrome in some cases. Patients should be carefully observed, particularly during treatment initiation and during dose adjustments. Discontinue the serotonergic medications if serotonin syndrome is suspected. [28343] [31266] [49444] [64391] Sevoflurane: (Major) Concomitant use of ondansetron and halogenated anesthetics increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28457] [28458] [28754] [28755] [28756] [31266] [32722] Siponimod: (Major) Concomitant use of siponimod and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [64031] Sodium Stibogluconate: (Major) Concomitant use of sodium stibogluconate and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [64608] Sofosbuvir; Velpatasvir; Voxilaprevir: (Moderate) Plasma concentrations of ondansetron, a P-glycoprotein (P-gp) substrate, may be increased when administered concurrently with voxilaprevir, a P-gp inhibitor. Monitor patients for increased side effects if these drugs are administered concurrently. [31266] [34653] [62131] Solifenacin: (Major) Concomitant use of solifenacin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [30515] [31266] [9564] Sorafenib: (Major) Concomitant use of sorafenib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [31832] Sotalol: (Major) Concomitant use of ondansetron and sotalol increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [28234] [31266] St. John's Wort, Hypericum perforatum: (Minor) St. John's Wort may reduce the efficacy of ondansetron by decreasing its systemic exposure; however, based on available data, no ondansetron dosage adjustment is recommended. If used together, monitor patients for antiemetic efficacy. St. John's Wort is a strong CYP3A inducer. Ondansetron is a substrate for CY1A2, CYP2D6, and CYP3A4, with CYP3A4 playing a predominant role in ondansetron turnover. During pharmacokinetic studies, patients treated with strong CYP3A inducers (i.e., phenytoin, carbamazepine, rifampin) and ondansetron had significantly increased ondansetron clearance, resulting in significant reductions in AUC, Cmax, and half-life. However, these changes in ondansetron exposure are not thought to be clinically relevant. [31266] [57202] Sufentanil: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering sufentanil with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [30966] [31266] [31723] [49446] Sunitinib: (Major) Concomitant use of sunitinib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [31970] [32722] Tacrolimus: (Major) Concomitant use of tacrolimus and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [27353] [27354] [28225] [31266] [32722] Tamoxifen: (Major) Concomitant use of ondansetron and tamoxifen increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [31266] [61870] [61871] [61872] [63589] Tapentadol: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering tapentadol with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risks and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. [28308] [31266] [31723] [36077] [49446] Telavancin: (Major) Concomitant use of telavancin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [36615] Tetrabenazine: (Major) Concomitant use of tetrabenazine and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [34389] Thioridazine: (Contraindicated) Avoid concomitant use of thioridazine and ondansetron due to an increased risk for torsade de pointes (TdP) and QT/QTc prolongation. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32722] [43069] Tolterodine: (Major) Due to the potential for QT prolongation and torsade de pointes (TdP), caution is advised when administering tolterodine with ondansetron. If these drugs must be coadministered, ECG monitoring is recommended. Tolterodine has been associated with dose-dependent prolongation of the QT interval, especially in poor CYP2D6 metabolizers. Ondansetron has been associated with QT prolongation and post-marketing reports of TdP. Among 42 patients receiving a 4 mg bolus dose of intravenous ondansetron for the treatment of postoperative nausea and vomiting, the mean maximal QTc interval prolongation was 20 +/- 13 msec at the third minute after antiemetic administration (p < 0.0001). Risk for QT prolongation increases with increased dosage, and a 32 mg IV dose must no longer be used for prevention of chemotherapy induced emesis. [31112] [31266] [9564] Tolvaptan: (Moderate) Coadministration of tolvaptan and hypertonic saline (e.g., 3% NaCl injection solution) is not recommended. The use of hypertonic sodium chloride in combination with tolvaptan may result in a too rapid correction of hyponatremia and increase the risk of osmotic demyelination (i.e., central pontine myelinolysis). [35780] Toremifene: (Major) Concomitant use of toremifene and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28822] [31266] [32722] Tramadol: (Moderate) Monitor for opioid withdrawal and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant ondansetron and tramadol use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. Also, data from 2 small trials indicate that concomitant use of ondansetron may result in reduced analgesic activity of tramadol; patients receiving ondansetron used tramadol more frequently leading to an increased cumulative dose in patient-controlled administration of tramadol. [28314] [30857] [31266] Tramadol; Acetaminophen: (Moderate) Monitor for opioid withdrawal and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant ondansetron and tramadol use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. Also, data from 2 small trials indicate that concomitant use of ondansetron may result in reduced analgesic activity of tramadol; patients receiving ondansetron used tramadol more frequently leading to an increased cumulative dose in patient-controlled administration of tramadol. [28314] [30857] [31266] Tranylcypromine: (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant monoamine oxidase inhibitor (MAOI) and ondansetron use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. [27957] [29656] [31266] [53440] Trazodone: (Major) Concomitant use of ondansetron and trazodone increases the risk of QT/QTc prolongation, torsade de pointes (TdP), and serotonin syndrome. Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. If concomitant use is necessary, consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, and monitor for serotonin syndrome. [31266] [32722] [38831] Triclabendazole: (Major) Concomitant use of triclabendazole and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [63962] Trifluoperazine: (Minor) Due to a possible risk for QT prolongation and torsade de pointes (TdP), ondansetron and trifluoperazine should be used together cautiously. Ondansetron has been associated with QT prolongation and post-marketing reports of torsade de pointes (TdP). Among 42 patients receiving a 4 mg bolus dose of intravenous ondansetron for the treatment of postoperative nausea and vomiting, the mean maximal QTc interval prolongation was 20 +/- 13 msec at the third minute after antiemetic administration (p < 0.0001). If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. Trifluoperazine, a phenothiazine, is associated with a possible risk for QT prolongation. [28415] [31266] [9564] Triptorelin: (Major) Concomitant use of triptorelin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [45411] Vandetanib: (Major) Concomitant use of vandetanib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [43901] Vardenafil: (Major) Concomitant use of ondansetron and vardenafil increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. [28216] [31266] Vemurafenib: (Major) Concomitant use of vemurafenib and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [30855] [31266] [32722] [45335] Venlafaxine: (Major) Concomitant use of ondansetron and venlafaxine increases the risk of QT/QTc prolongation, torsade de pointes (TdP), and serotonin syndrome. Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. If concomitant use is necessary, consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, and monitor for serotonin syndrome. [31266] [32722] [33715] Vilazodone: (Major) Because of the potential risk and severity of serotonin syndrome, use caution when administering ondansetron with other drugs that have serotonergic properties such as vilazodone. If serotonin syndrome is suspected, discontinue ondansetron and concurrent serotonergic agents and initiate appropriate medical treatment. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. [31266] [43177] Voclosporin: (Major) Concomitant use of voclosporin and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. The degree of QT prolongation associated with voclosporin is not clinically significant when administered within the recommended dosage range; QT prolongation has been described at 3 times the maximum recommended dose. [31266] [66336] Vonoprazan; Amoxicillin; Clarithromycin: (Major) Concomitant use of ondansetron and clarithromycin increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28225] [28238] [31266] [32722] Voriconazole: (Major) Caution is advised when administering voriconazole with drugs that are known to prolong that QT interval and are metabolized by CYP3A4, such as ondansetron. Ondansetron has been associated with QT prolongation and postmarketing reports of torsade de pointes (TdP). Voriconazole has been associated with QT prolongation and rare cases of TdP, cardiac arrest, and sudden death. Use of these drugs together increases the risk for QT prolongation. If ondansetron and another drug that prolongs the QT interval must be coadministered, ECG monitoring is recommended. In addition, coadministration of voriconazole (a strong CYP3A4 inhibitor) with ondansetron (a CYP3A4 substrate) may result in elevated ondansetron plasma concentrations and could increase the risk for adverse events, including QT prolongation. If these drugs are given together, closely monitor for prolongation of the QT interval. Rigorous attempts to correct any electrolyte abnormalities (i.e., potassium, magnesium, calcium) should be made before initiating concurrent therapy. [28158] [31266] [32722] Vorinostat: (Major) Concomitant use of vorinostat and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [31266] [32789] Ziprasidone: (Major) Concomitant use of ziprasidone and ondansetron increases the risk of QT/QTc prolongation and torsade de pointes (TdP). Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. Do not exceed 16 mg of IV ondansetron in a single dose; the degree of QT prolongation associated with ondansetron significantly increases above this dose. [28233] [31266] Zonisamide: (Minor) Zonisamide is a weak inhibitor of P-glycoprotein (P-gp), and ondansetron is a substrate of P-gp. There is theoretical potential for zonisamide to affect the pharmacokinetics of drugs that are P-gp substrates. Use caution when starting or stopping zonisamide or changing the zonisamide dosage in patients also receiving drugs which are P-gp substrates. [28843] [31266] [34653]
Revision Date: 02/02/2023, 02:26:00 AM

References

6742 - Manoguerra AS, Krenzelok EP. Rapid emesis from high-dose ipecac syrup in adults and children intoxicated with antiemetics or other drugs. Am J Hosp Pharm 1978;35(11):1360-1362.7619 - Zofran® (ondansetron) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2004 May.9564 - Charbit B, Albaladejo P, Funck-Brentano C, et al. Prolongation of QTc interval after postoperative nausea and vomiting treatment by droperidol or ondansetron. Anesthesiology 2005;102:1094-100.11416 - Lee CG, Gottesman MM, Cardarelli CO. HIV-1 protease inhibitors are substrates for the MDR1 multidrug transporter. Biochemistry 1998;37:3594-601.11417 - Storch CH, Theile D, Lindenmaier H, et al. Comparison of inhibitory activity of anti-HIV drugs on P-glycoprotein. Biochem Pharmacol 2007;73:1573-81.11512 - Schinkel AH, Wagenaar E, Mol C, et al. P-glycoprotein in the blood-brain barrier of mice influences the brain penetration and pharmacological activity of many drugs. J Clin Invest 1996;97:2517-2524.22005 - Perucca E. Clinically relevant drug interactions with antiepileptic drugs. Br J Clin Pharmacol 2006;61(3):246-255.23500 - Wilt JL, Minnema AM, Johnson RF, et al. Torsade de pointes associated with the use of intravenous haloperidol. Ann Intern Med 1993;119:391-4.23620 - Green PT, Reents S, Harman E, et al. Pentamidine-induced torsades de pointes in a renal tranplant recipient with Pneumocystis carinii pneumonia. S Med J 1990;83:481-4.23774 - Lui HK, Lee G, Dietrich P, et al. Flecainide-induced QT prolongation and ventricular tachycardia. Am Heart J 1982;103:567-9.23778 - Wharton JM, Demopulos PA, Goldschlager N. Torsade de pointes during administration of pentamidine isethionate. Am J Med 1987;83:571-6.23779 - Kriwisky M, Perry GY, Tarchitsky D, et al. Haloperidol-induced torsades de pointes. Chest 1990;98:482-3.26045 - Villikka K, Kivisto KT, Neuvonen PJ. The effect of rifampin on the pharmacokinetics of oral and intravenous ondansetron. Clin Pharmacol Ther 1999;65:377-81.27353 - Hodak SP, Moubarak JB, Rodriguez I, et al. QT Prolongation and near fatal cardiac arrhythmia after intravenous tacrolimus administration: a case report. Transplantation 1998;66:535-7.27354 - Johnson MC, So S, Marsh JW, et al. QT prolongation and Torsades de Pointes after administration of FK506. Transplantation 1992;53:929-30.27957 - Nardil (phenelzine) tablet package insert. New York, NY: Pfizer; 2009 Feb.27982 - Ketoconazole tablets package insert. Morgantown, WV: Mylan Pharmaceuticals, Inc.; 2017 Sept.28001 - Hansten PD, Horn JR. Cytochrome P450 Enzymes and Drug Interactions, Table of Cytochrome P450 Substrates, Inhibitors, Inducers and P-glycoprotein, with Footnotes. In: The Top 100 Drug Interactions - A guide to Patient Management. 2008 Edition. Freeland, WA: H&H Publications; 2008:142-157.28142 - Reyataz (atazanavir) package insert. Princeton, NJ: Bristol-Myers Squibb Company; 2020 Sept.28158 - VFEND (voriconazole) tablets, suspension, and injection package insert. New York, NY: Pfizer Inc; 2022 Oct.28216 - Levitra (vardenafil) package insert. Kenilworth, NJ: Schering-Plough; 2017 Aug.28221 - Tikosyn (dofetilide) package insert. New York, NY: Pfizer Labs; 2019 Aug.28224 - Pacerone (amiodarone) tablets package insert. Maple Grove, MN: Upsher-Smith Laboratories, LLC.; 2018 Nov.28225 - CredibleMeds. Drugs to avoid in congenital long QT. Available on the World Wide Web at http://www.crediblemeds.org.28226 - Trisenox (arsenic trioxide) package insert. Frazer, PA: Cephalon, Inc; 2010 Jun.28229 - Demaziere J, Fourcade JM, Busseuil CT, et al. The hazards of chloroquine self prescription in west Africa. J Toxicol Clin Toxicol 1995;33:369-70.28230 - Mansfield RJ, Thomas RD. Recurrent syncope. Drug induced long QT syndrome. Postgrad Med J 2001;77:344, 352-3.28231 - Pinski SL, Eguia LE, Trohman RG. What is the minimal pacing rate that prevents torsades de pointes? Insights from patients with permanent pacemakers. Pacing Clin Electrophysiol 2002;25:1612-5.28233 - Geodon (ziprasidone) package insert. New York, NY: Pfizer: 2021 May.28234 - Betapace (sotalol) package insert. Wayne, NJ: Berlex Laboratories; 2011 Aug.28235 - Richards JR, Schneir AB. Droperidol in the emergency department: is it safe? J Emerg Med 2003;24:441-7.28236 - Kao LW, Kirk MA, Evers SJ, et al. Droperidol, QT prolongation, and sudden death: what is the evidence? Ann Emerg Med 2003;41:546-58.28238 - Biaxin (clarithromycin) package insert. North Chicago, IL: AbbVie, Inc.; 2019 Sep.28250 - Procanbid (procainamide) package insert. Bristol, TN: Monarch Pharmaceuticals; 2002 Jan.28251 - Ery-tab (erythromycin delayed-release tablets) package insert. Atlanta, GA: Arbor Pharmaceuticals, Inc.; 2018 Oct.28260 - Paxil (paroxetine) tablet package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Seot.28261 - Uroxatral (alfuzosin extended-release tablets) package insert. St. Michael, Barbados: Concordia Pharmaceuticals, INC.; 2015 May.28262 - Clozaril (clozapine) tablets package insert. Rosemont, PA: HLS Therapeutics (USA), Inc.; 2022 Dec.28269 - Celexa (citalopram) tablets package insert. Madison, NJ: Allergan USA, Inc.; 2022 Feb.28270 - Lexapro (escitalopram) package insert. Madison, NJ: Allergan USA, Inc.; 2021 Sept.28287 - Rythmol SR (propafenone hydrochloride) capsule extended release package insert. Research Triangle Park, NC: GlaxoSmithKline; 2018 Nov.28301 - Mefloquine package insert. Princeton, NJ: Sandoz Inc.; 2013 Jul.28307 - Haldol (haloperidol) injection for immediate release package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2020 Feb.28308 - Anzemet (dolasetron mesylate) tablets package insert. Bridgewater, NJ: Sanofi-Aventis U.S. LLC; 2014 Sept.28314 - Ultram (tramadol immediate-release tablets) package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2021 Sep.28319 - Krantz MJ, Kutinsky IB, Robertson AD, et al. Dose-related effects of methadone on QT prolongation in a series of patients with torsade de pointes. Pharmacotherapy 2003;23:802-5.28320 - Walker PW, Klein D, Kasza L. High dose methadone and ventricular arrhythmias: a report of three cases. Pain 2003;103:321-4.28321 - Kornick CA, Kilborn MJ, Santiago-Palma J, et al. QTc interval prolongation associated with intravenous methadone. Pain 2003;105:499-506.28322 - Gil M, Sala M, Anguera I, et al. QT prolongation and Torsades de Pointes in patients infected with human immunodeficiency virus and treated with methadone. Am J Cardiol 2003;92:995-7.28341 - Kaletra (lopinavir; ritonavir) tablet and solution package insert. North Chicago, IL: AbbVie Inc; 2020 Oct.28343 - Zoloft (sertraline) package insert. Morgantown, WV: Viatris Specialty LLC; 2023 Jan.28377 - Foscavir (foscarnet) package insert. Lake Forest, IL: Clinigen Healthcare, Ltd.; 2017 Feb.28379 - Methadone Hydrochloride Injection package insert. Wilmington, NC: AAI Pharma; 2004 Feb.28405 - Strattera (atomoxetine) package insert. Indianapolis, IN: Eli Lilly and Company; 2022 Jan.28414 - Risperdal (risperidone tablets, oral solution, and orally disintegrating tablets) package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2022 Aug.28415 - Nora Goldschlager, Andrew E Epstein, Blair P Grubb, et al. Etiologic considerations in the patient with syncope and an apparently normal heart. Arch Intern Med 2003;163:151-62.28416 - Hansten PD, Horn JR. Drug Interactions with Drugs that Increase QTc Intervals. In: The Top 100 Drug Interactions - A Guide to Patient Management. 2007 Edition. Freeland, WA: H&H Publications; 2007:144-8.28417 - Hoehns JD, Stanford RH, Geraets DR, et al. Torsades de pointes associated with chlorpromazine: case report and review of associated ventricular arrhythmias. Pharmacotherapy 2001;21:871-83.28419 - Owens RC Jr. Risk assessment for antimicrobial agent-induced QTc interval prolongation and torsades de pointes. Pharmacotherapy 2001;21:301-19.28420 - Iannini PB. Cardiotoxicity of macrolides, ketolides and fluoroquinolones that prolong the QTc interval. Expert Opin Drug Saf 2002;1:121-8.28421 - Levaquin (levofloxacin) tablet package insert. Titusville, NJ: Janssen Pharmaceutical, Inc.; 2020 Jun.28423 - Avelox (moxifloxacin) package insert. Whippany, NJ: Bayer HealthCare Pharmaceuticals Inc.; 2020 May.28424 - Factive (gemifloxacin mesylate) package insert. Toronto, ON: Merus Labs International, Inc.; 2019 May.28432 - Roden, DM. Drug-induced prolongation of the QT interval. New Engl J Med 2004;350:1013-22.28442 - Sustiva (efavirenz) package insert. Princeton, NJ: Bristol-Myers Squibb Company; 2019 Oct.28445 - Zomig (zolmitriptan) tablets package insert. Hayward, CA: Impax Specialty Pharma; 2018 Dec.28457 - Crouch MA, Limon L, Cassano AT. Clinical relevance and management of drug-related QT interval prolongation. Pharmacotherapy 2003;23:881-908.28458 - Schmeling WT, Warltier DC, McDonald DJ, et al. Prolongation of the QT interval by enflurane, isoflurane, and halothane in humans. Anesth Analg 1991;72:137-44.28548 - Suboxone (buprenorphine and naloxone) sublingual tablets package insert. Hull, UK: Reckitt Benckiser Healthcare (UK) Ltd.; 2022 Jun.28583 - Imitrex (sumatriptan succinate) tablets package insert. Research Triangle Park, NC: GlaxoSmithKline; 2017 Dec.28592 - Zoladex (goserelin acetate 3.6 mg implant) package insert. Lake Forest, IL: TerSera Therapeutics LLC; 2019 Feb.28599 - Zyvox (linezolid) package insert. New York, NY: Pharmacia and Upjohn Company; 2021 Oct.28654 - Lithium carbonate extended-release tablet 450-mg package insert. Morgantown, WV: Mylan Pharmaceuticals, Inc; 2020 Feb.28661 - Apokyn and Apokyn Pen (apomorphine) injection package insert. Rockville, MD: MMD US Operations, LLC; 2022 Jun28674 - Diflucan oral tablet and suspension (fluconazole) package insert. New York, NY: Pfizer; 2023 Jan.28737 - Inapsine (Droperidol) Injection package insert. Lake Forest, IL: Akorn, Inc.; 2011 Oct.28752 - Thevenin J, Da Costa A, Roche F, et al. Flecainide induced ventricular tachycardia (torsades de pointes). Pacing Clin Electrophysiol 2003;26:1907-8.28754 - Loeckinger A, Kleinsasser A, Maier S, et al. Sustained prolongation of the QTc interval after anesthesia with sevoflurane in infants during the first 6 months of life. Anesthesiology 2003;98:639-42.28755 - Kleinsasser A, Loeckinger A, Lindner KH, et al. Reversing sevoflurane-associated Q-Tc prolongation by changing to propofol. Anaesthesia 2001;56:248-50.28756 - Kuenszberg E, Loeckinger A, Kleinsasser A, et al. Sevoflurane progressively prolongs the QT interval in unpremedicated female adults. Eur J Anaesthesiol 2000;17:662-4.28759 - Maprotiline HCl tablet package insert. Morgantown WV: Mylan Pharmaceuticals Inc; 2014 Dec.28775 - Owens RC. QT Prolongation with antimicrobial agents: Understanding the significance. Drugs 2004;64:1091-1124.28785 - Zyprexa (olanzapine, all formulations) package insert. Indianapolis, IN: Eli Lilly and Company; 2020 Apr.28822 - Fareston (toremifene citrate) tablets package insert. Bedminster, NJ: Kyowa Kirin Inc.; 2017 May.28843 - Zonegran (zonisamide) package insert. Dublin, Ireland: Concordia Pharmaceuticals, Inc.; 2020 Apr.28855 - Zithromax (azithromycin 250 mg and 500 mg tablets and azithromycin oral suspension) package insert. New York, NY: Pfizer Inc.; 2021 Nov.28879 - Pentamidine isethionate injection package insert. East Brunswick, NJ: Avet Pharmaceuticals Inc.; 2021 Jan.28896 - Yamreudeewong W, DeBisschop M, Martin LG, et al. Potentially significant drug interactions of class III antiarrhythmic drugs. Drug Saf 2003;26:421-38.28897 - Ultiva (remifentanil) package insert. Rockford, IL: Mylan Institutional LLC; 2019 Oct.28995 - Invirase (saquinavir) package insert. South San Francisco, CA: Genentech Inc.; 2020 Sept.29012 - Lexiva (fosamprenavir calcium) package insert. Research Triangle Park, NC: ViiV Healthcare; 2019 Mar29036 - Venkatakrishnan K, von Moltke LL, Greenblatt DJ. Effects of the antifungal agents on oxidative drug metabolism. Clin Pharmacokinet 2000;38:111-180.29103 - Pea F, Furlanut M. Pharmacokinetic aspects of treating infections in the intensive care unit. Clin Pharmacokinet 2001;40(11):833-868.29113 - Sandostatin (octreotide) package insert. East Hanover, NJ: Novartis Pharmaceuticals Corporation; 2023 Oct.29118 - Seroquel (quetiapine fumarate) package insert. Wilmington, DE: AstraZeneca Pharmaceuticals LP; 2022 Jan.29121 - Relpax (eletriptan hydrobromide) package insert. New York, NY: Pfizer Inc.; 2020 Mar.29266 - Frova (frovatriptan) package insert. Malvern, PA: Endo Pharmaceuticals, Inc.; 2018 Aug.29267 - Amerge (naratriptan hydrochloride) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2016 Nov.29656 - Parnate (tranylcypromine) package insert. St. Michael, Barbados: Concordia Pharmaceuticals; 2018 Jan.29758 - Aralen (chloroquine) package insert. Bridgewater, NJ: Sanofi-aventis U.S. LLC.; 2018 Oct.29833 - Frothingham R. Rates of torsades de pointes associated with ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin, and moxifloxacin. Pharmacotherapy 2001;21:1468-72.30072 - Alfentanil hydrochloride injection package insert. Lake Forest, IL: Akorn, Inc.; 2019 Oct.30106 - Imodium A-D Liquid and Caplets (loperamide HCL) consumer product labels. Fort Washington, PA: Johnson and Johnson Consumer Inc., McNeil Consumer Healthcare Division; 2019.30163 - Agrylin (anagrelide) capsules package insert. Lexington, MA: Takeda Pharmaceuticals USA, Inc.; 2021 Oct.30282 - Synalgos-DC (aspirin; caffeine; dihydrocodeine) capsules package insert. Atlanta, GA: Mikart, Inc.; 2019 Oct.30369 - Vantas (histrelin implant) package insert. Chadds Ford, PA: Endo Pharmaceuticals Solutions Inc.; 2020 Dec.30515 - Vesicare (solifenacin) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2012 Jul.30624 - Herrington AM, George KW, Moulds CC. Octreotide-induced bradycardia. Pharmacotherapy 1998;18:413-6.30676 - Emend (aprepitant oral products) package insert. Whitehouse Station, NJ: Merck & Co.,Inc.; 2019 Nov.30738 - Ofloxacin tablets package insert. Sacramento, CA: Nivagen Pharmaceuticals, Inc.; 2019 Feb.30802 - Hansten PD, Horn JR. Top 100 Drug Interactions Monographs. In: The Top 100 Drug Interactions - A guide to Patient Management. 2007 Edition. Freeland, WA: H&H Publications; 2007:4-141.30830 - Skelaxin (metaxalone) tablet package insert. Bristol, TN: King Pharmaceuticals, Inc.; 2018 Mar.30855 - Zofran® (ondansetron) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2004 May.30857 - Arcioni R, della Rocca M, Romano S, et al. Ondansetron inhibits the analgesic effects of tramadol: a possible 5-HT(3) spinal receptor involvement in acute pain in humans. Anesth Analg 2002;94:1553-7.30966 - Sufenta (sufentanil citrate injection) package insert. Lake Forest, IL: Akorn Pharmaceuticals, Inc.; 2019 Oct30988 - Demerol (meperidine hydrochloride injection) package insert. Lake Forest, IL: Hospira, Inc.; 2019 Oct.31112 - Detrol (tolterodine tartrate) package insert. New York, NY: Pharmacia and Upjohn Co., division of Pfizer; 2016 Nov.31266 - Zofran (ondansetron) injection package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 Oct.31403 - Qualaquin (quinine sulfate) capsules package insert. Cranbury, NJ: Sun Pharmaceutical Industries, Inc.; 2019 Jun.31723 - Kytril injection (granisetron) package insert. Nutley, NJ: Roche Pharmaceuticals; 2011 Nov.31832 - Nexavar (sorafenib) package insert. Wayne, NJ; Bayer HealthCare Pharmaceuticals Inc.; 2020 July.31864 - Maxalt and Maxalt-MLT (rizatriptan) package insert. Whitehouse Station, NJ: Merck and Co Inc.; 2019 Oct.31869 - Axert (almotriptan) package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2017 May.31909 - Aloxi (palonosetron hydrochloride) injection package insert. Woodcliff Lake, NJ: Eisai Inc.;2020 April.31938 - Ranexa (ranolazine extended-release tablets) package insert. Foster City, CA: Gilead Sciences, Inc. 2019 Oct.31970 - Sunitinib (Sutent) package insert. New York, NY: Pfizer Labs; 2020 Aug.32026 - Emsam (selegiline) transdermal system package insert. Morgantown, WV: Somerset Pharmaceuticals, Inc.; 2020 May.32127 - Prozac (fluoxetine) capsules package insert. Indianapolis, IN: Eli Lilly and Company; 2021 Oct.32432 - Prezista (darunavir) package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2022 Oct.32436 - Zelapar (selegiline orally-disintegrating tablets) package insert. Bridgewater, NJ: Bausch Health U.S., LLC; 2021 Jun.32438 - Opana (oxymorphone hydrochloride) tablets package insert. Malvern, PA: Endo Pharmaceuticals, Inc.; 2019 Oct.32722 - Charbit B, Albaladejo P, Funck-Brentano C, et al. Prolongation of QTc interval after postoperative nausea and vomiting treatment by droperidol or ondansetron. Anesthesiology 2005;102:1094-100.32723 - Noxafil (posaconazole) package insert. Whitehouse Station, NJ: Merck & Co. Inc.: 2022 Jan.32732 - Stollberger C, Huber JO, Finsterer J. Antipsychotic drugs and QT prolongation. Int Clin Psychopharmacol 2005;20:243-51.32734 - Su KP, Lane HY, Chuang CL, et al. Olanzapine-induced QTc prolongation in a patient with wolff-parkinson-white syndrome. Schizophrenia Research 2004;66:191-2.32745 - Dineen S, Withrow K, Voronovitch L, et al. QTc prolongation and high-dose olanzapine. Psychosomatics 2003;44:174-5.32746 - Gurovich, I. QTc prolongation: chlorpromazine and high-dosage olanzapine. Can J Psychiatry 2003;48:348.32789 - Zolinza (vorinostat) capsules package insert. Whitehouse Station, NJ: Merck & Co., Inc.; 2018 Dec.33068 - Gajwani P, Pozuelo L, Tesar G, et al. QT interval prolongation associated with quetiapine (seroquel) overdose. Psychosomatics 2000;41:63-5.33072 - Beelen AP, Yeo KTJ, Lewis LD. Asymptomatic QTc prolongation associated with quetiapine fumarate overdose in a patient being treated with risperidone. Hum Exp Toxicol 2001;20:215-9.33074 - Furst BA, Champion KM, Pierre JM, et al. Possible association of QTc interval prolongation with co-administration of quetiapine and lovastatin. Biol Psychiatry 2002;51:264-5.33136 - Dolophine (methadone) tablets package insert. Eatontown, NJ: West-Ward Pharmaceuticals Corp.; 2021 Jun.33192 - Tykerb (lapatinib) tablet package insert. Research Triangle Park, NC: GlaxoSmithKline; 2018 Dec.33557 - Tasigna (nilotinib) package insert. East Hanover, NJ: Novartis Pharmaceuticals Corporation; 2015 Oct.33654 - Codeine sulfate tablets package insert. Eatontown, NJ; West-Ward Pharmaceuticals Corp.: 2021 Mar.33715 - Effexor XR (venlafaxine extended-release capsules) package insert. Philadelphia, PA: Wyeth Pharmaceuticals, Inc; 2022 Aug.33718 - Intelence (etravirine) package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2019 July.34335 - Giao PT, de Vries PJ. Pharmacokinetic interactions of antimalarial agents. Clin Pharmacokinet 2001;40:343-73.34353 - Ducharme J, Farinotti R. Clinical pharmacokinetics and metabolism of chloroquine: focus on recent advancements. Clin Pharmacokinet 1996;31:257-74.34389 - Xenazine (tetrabenazine) package insert. Deerfield, IL: Lundbeck, Inc.; 2017 Sep.34447 - Niwa T, Shiraga T, Takagi A. Effect of antifungal drugs on cytochrome P450 (CYP) 2C9, CYP2C19, and CYP3A4 activities in human liver microsomes. Biol Pharm Bull. 2005;28:1805-1808.34653 - Schinkel AH, Wagenaar E, Mol C, et al. P-glycoprotein in the blood-brain barrier of mice influences the brain penetration and pharmacological activity of many drugs. J Clin Invest 1996;97:2517-2524.34883 - Promethazine and codeine oral solution package insert. Baudette, MN: ANI Pharmaceuticals, Inc.; 2018 Jun.35401 - Coartem (artemether; lumefantrine) package insert. East Hanover, NJ: Novartis Pharmaceuticals Corporation; 2019 Aug.35780 - Samsca (tolvaptan) package insert. Rockville, MD: Otsuka America Pharmaceutical, Inc.; 2021 Apr.36077 - Nucynta (tapentadol immediate-release tablets) package insert. Stoughton, MA; Collegium Pharmaceutical, Inc.: 2021 Mar.36101 - Multaq (dronedarone) package insert. Bridgewater, NJ: Sanofi-aventis U.S. LLC; 2020 Nov.36146 - Fanapt (iloperidone) package insert. Rockville, MD: Vanda Pharmaceuticals, Inc.; 2017 Mar.36343 - Saphris (asenapine) sublingual tablet package insert. St. Louis, MO: Forest Pharmaceuticals, Inc.; 2017 Mar.36615 - Vibativ (telavancin) package insert. Nashville, TN: Cumberland Pharmaceuticals Inc.; 2020 July.36894 - Metronidazole injection package insert. Deerfield, IL: Baxter Healthcare Corporation; 2021 Dec.37098 - Votrient (pazopanib) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2011 Oct.37292 - Istodax (romidepsin) injection package insert. Summit, NJ: Celgene Corporation; 2021 July.38831 - Oleptro (trazodone hydrochloride) extended-release tablets package insert. Dublin, Ireland: Labopharm Europe Limited; 2014 Jul.39156 - Food and Drug Administration MedWatch. Invirase (saquinavir): ongoing safety review of clinical trial data. Retrieved Feb. 24, 2010. Available on the World Wide Web at http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm201563.htm.39635 - Exalgo (hydromorphone hydrochloride) extended-release tablets package insert. Hazelwood, MO: Mallinckrodt Brand Pharmaceuticals Inc.; 2019 Oct.40027 - Emend (fosaprepitant dimeglumine injection) package insert. Whitehouse Station, NJ: Merck & Co.,Inc.; 2022 May.40233 - Sporanox (itraconazole) oral solution package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2022 Dec.40241 - Zofran (ondansetron) package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.40936 - Invega Sustenna (paliperidone palmitate injectable suspension) package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2022 Jul.40942 - Remeron and Remeron SolTabs (mirtazapine tablets and ODT tablets) package insert. Whitehouse Station, NJ: Merck Sharp & Dohme Corp.; 2021 Nov.40944 - Sublimaze (fentanyl citrate injection) package insert. Lake Forest, IL: Akorn, Inc.; 2019 Oct.40951 - MS Contin (morphine sulfate extended-release tablets) package insert. Stamford, CT: Purdue Pharma L.P.; 2021 Mar.41453 - Buprenex (buprenorphine hydrochloride) injection solution package insert. North Chesterfield, VA: Indivior, Inc.; 2019 Oct.41806 - Plaquenil (hydroxychloroquine) package insert. St. Michael, Barbados: Concordia Pharmaceuticals, Inc.; 2022 May.41830 - Corvert (ibutilide) package insert. New York, NY: Pharmacia and Upjohn Company; 2016 Aug.41934 - Lysodren (mitotane) package insert. Princeton, NJ: Bristol-Myers Squibb Oncology; 2021 June.41958 - Eloxatin (oxaliplatin) package insert. Bridgewater, NJ: Sanofi-aventis U.S. LLC; 2020 April.41984 - Primaquine phosphate package insert. Bridgewater, NJ: Sanofi-aventis; 2017 Jun.42029 - Opana (oxymorphone injection) package insert. Malvern, PA: Endo Pharmaceuticals, Inc.; 2019 Sept42280 - Nuedexta (dextromethorphan hydrobromide; quinidine sulfate capsule) package insert. Aliso Viejo, CA: Avanir Pharmaceuticals, Inc.; 2019 Jun.42449 - Halaven (eribulin mesylate) injection package insert. Woodcliffe Lake, NJ: Eisai Inc.; 2022 Sept.42844 - FDA Drug Safety Communication: Abnormal heart rhythms associated with use of Anzemet (dolasetron mesylate). Retrieved December 17, 2010. Available on the World Wide Web at: http://www.fda.gov/Drugs/DrugSafety/ucm237081.htm.42845 - Abilify (aripiprazole) tablets, discmelt orally-disintegrating tablets, oral solution, and intramuscular injection package insert. Rockville, MD: Otsuka America Pharmaceutical, Inc.; 2022 Nov.43065 - Chlorpromazine package insert. Princeton, NJ: Sandoz Inc; 2019 Dec.43069 - Thioridazine package insert. Philadelphia, PA:Mutual Pharmaceutical Company, Inc;2010 Sept.43177 - Viibryd (vilazodone) tablets package insert. Madison, NJ; Allergan USA, Inc.: 2021 July.43291 - Norco (hydrocodone bitartrate and acetaminophen) tablet package insert. Madison, NJ: Allergan USA, Inc.; 2019 Oct.43411 - Cipro (ciprofloxacin tablet; suspension) package insert. Whippany, NJ: Bayer HealthCare Pharmaceuticals Inc.; 2021 Nov.43463 - Orap (pimozide) package insert. Sellersville, PA: Teva Pharmaceuticals USA; 2014 Mar.43800 - Lupron Depot (leuprolide acetate for depot suspension) package insert. North Chicago, IL: AbbVie Inc; 2022 April43901 - Caprelsa (vandetanib) package insert. Wilmington, DE: AstraZeneca Pharmaceuticals LP; 2022 March.43906 - Roxicodone (oxycodone) tablet package insert. Webster Groves, MO: Mallinckrodt Pharmaceuticals, Inc.; 2021 Mar.44061 - Percocet (acetaminophen and oxycodone hydrochloride) tablets package insert. Malvern, PA: Endo Pharmaceuticals Inc.; 2020 Aug.44376 - Edurant (rilpivirine) package insert. Titusville, NJ: Janssen Therapeutics; 2022 Oct.45335 - Zelboraf (vemurafenib) tablet package insert. South San Francisco, CA: Genentech USA, Inc.; 2020 May.45411 - Trelstar (triptorelin pamoate for injectable suspension) package insert. Ewing, NJ: Verity Pharmaceuticals, Inc.; 2021 Dec.45458 - Xalkori (crizotinib) package insert. New York, NY: Pfizer Labs; 2022 July.46350 - Morphine sulfate tablet package insert. Berkley Heights, NJ: Hikma Pharmaceuticals Corp; 2021 Jun.46869 - Firmagon (degarelix) package insert. Parsippany, NJ: Ferring Pharmaceuticals Inc.; 2020 Dec.47129 - Hydroxyzine hydrochloride injection package insert. Shirley, NY: American Regent, Inc.; 2016 Oct.47165 - Norvir (ritonavir tablets, solution, and powder) package insert. North Chicago, IL: AbbVie Inc; 2020 Oct.47221 - Propulsid (cisapride) package insert. Titusville, NJ; Janssen Pharmaceutica; 2006 Oct. NOTE: As of May 2000; Propulsid has only been available in the United States via an investigational limited access program to ensure proper patient screening and prescribing.47357 - Quinidine gluconate extended-release tablet package insert. Princeton, NJ: Eywa Pharma Inc.; 2021 Dec.48697 - Korlym (mifepristone) tablet package insert. Menlo Park, CA: Corcept Therapeutics; 2019 Nov.48869 - Briasoulis A, Agarwal V, Pierce WJ. QT prolongation and tosade de pointes induced by fluoroquinolones: infrequent side effects from commonly used medications. Cardiology 2011;120:103-10.49444 - Ondansetron hydrochloride (Zofran) tablets and oral solution package insert. Research Triangle Park, NC: GlaxoSmithKline; 2021 April.49446 - Aloxi (palonosetron hydrochloride) injection package insert. Woodcliff Lake, NJ: Eisai Inc.;2020 April.49619 - Dilaudid (hydromorphone) injection package insert. Lake Zurich, IL: Fresenius Kabi; 2019 Oct.49631 - Nalbuphine hydrochloride injection package insert. Lake Forest, IL; Hospira, Inc.; 2020 Feb.49815 - Sancuso (granisetron) patch package insert. Bedminster, NJ: ProStrakan, Inc.; 2020 April.50507 - Luvox CR (fluvoxamine maleate extended-release capsules) package insert. Palo Alto, CA: Jazz Pharmaceuticals, Inc.; 2017 Jan.51111 - Myrbetriq (mirabegron extended-release tablets and oral suspension) package insert. Northbrook, Illinois: Astellas Pharma US, Inc.; 2021 March.51182 - Demerol (meperidine tablets and oral solution) package insert. Parsippany, NJ: Validus Pharmaceuticals, LLC; 2021 Mar.51289 - Inapsine (droperidol) package insert. Lake Forest, IL: Akorn, Inc.; 2011 Nov.51664 - Stribild (elvitegravir; cobicistat; emtricitabine; tenofovir disoproxil fumarate) package insert. Foster City, CA: Gilead Sciences, Inc; 2021 Sept.52611 - Signifor (pasireotide diaspartate) package insert. Stein, Switzerland: Novartis Pharma Stein AG; 2020 Jan.52746 - Sirturo (bedaquiline) tablet package insert. Titusville, NJ: Janssen Therapeutics; 2021 Sept.53440 - Marplan (isocarboxazid) package insert. Parsippany, NJ: Validus Pharmaceuticals; 2018 Nov.55436 - Patsalos PN, Berry DJ, Bourgeois BF. Antiepileptic drugs--best practice guidelines for therapeutic drug monitoring: a position paper by the subcommission on therapeutic drug monitoring, ILAE Commission on Therapeutic Strategies. Epilepsia 2008;49:1239-1276.55578 - Owczuk R, Twardowski P, Dylczyk-Sommer A, et al. Influence of promethazine on cardiac repolarization: a double-blind, midazolam-controlled study. Anaesthesia 2009;64:609-614.55943 - Platman SR, Fieve RR. Lithium retention and excretion. The effect of sodium and fluid intake. Arch Gen Psychiatry 1969; 20 (3):285-9.56303 - Zohydro ER (hydrocodone extended-release capsules) package insert. Morristown, NJ: Currax Pharmaceuticals LLC; 2021 Mar.56579 - Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers. Updated Mar 10, 2020. Retrieved from the World Wide Web at www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/DrugInteractionsLabeling/ucm093664.htm57046 - Perucca E, Hedges A, Makki KA, et al. A comparative study of the relative enzyme inducing properties of anticonvulsant drugs in epileptic patients. Br J Clin Pharmacol 1984;18:401-10.57048 - Drug Development and Drug Interactions: Table of Substrates, Inhibitors and Inducers. Retrieved from the World Wide Web December 27, 2013. http://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/DrugInteractionsLabeling/ucm093664.htm#major57080 - de Leon J, Santoro V, D'Arrigo C, et al. Interactions between antiepileptics and second generation antipsychotics. Expert Opin Drug Metab Toxicol 2012;8:311-34.57094 - Zykadia (ceritinib) package insert. Indianapolis, IN: Novartis; 2021 Oct.57105 - Schuetz EG, Beck WT, Schuetz JD. Modulators and substrates of P-glycoprotein and cytochrome P4503A coordinately up-regulate these proteins in human colon carcinoma cells. Mol Pharmacol 1996;49:311-318.57202 - Zhou S, Chan E, Pan S, et al. Pharmacokinetic interactions of drugs with St John's wort. J Psychopharmacol 2004;18:262-76.57433 - Armahizer MJ, Seybert AL, Smithburger PL, et al. Drug-drug interaction contributing to QT prolongation in cardiac intensive care units. J Crit Care 2013;28:243-9.57434 - Dixon CM, Colthup PV, Serabjit-Singh CJ, et al. Multiple forms of cytochrome P450 are involved in the metabolism of ondansetron in humans. Drug Metab Dispos 1995;23:1225-30.57441 - Iribarren C, Round AD, Peng JA, et al. Validation of a population-based method to assess drug-induced alterations in QT interval: a self-controlled crossover study. Pharmacoepidemiol Drug Saf 2013;22;1222-32.57486 - Bruggemann RJM, Afllenaar JWC, Blijlevens NMA, et al. Clinical relevance of the pharmacokinetic interactions of azole antifungal drugs with other coadministered agents. Clin Infect Dis 2009;48:1441-58.57675 - Zydelig (idelalisib) tablet package insert. Foster City, CA:Gilead Sciences, Inc.; 2022 Feb.57741 - Orbactiv (oritavancin) package insert. Lincolnshire, IL: Melinta Therapeutics, LLC; 2022 Jan.57803 - Cerdelga (eliglustat) capsules. Waterford, Ireland: Genzyme Ireland, Ltd.;2018 Sept.58000 - Tybost (cobicistat) package insert. Foster City, CA: Gilead Sciences, Inc; 2021 Sept.58167 - Harvoni (ledipasvir; sofosbuvir) tablet and oral pellets package insert. Foster City, CA: Gilead Sciences, Inc; 2020 Mar.58572 - Trezix (acetaminophen 320.5 mg, caffeine 30 mg, dihydrocodeine 16 mg) capsule package insert. Ridgeland, MS: Wraser Pharmaceuticals; 2018 Jul.58782 - Lenvima (lenvatinib) package insert. Woodcliff Lake, NJ:Eisai Inc; 2022 Nov.58821 - Farydak (panobinostat) capsules package insert. Las Vegas, NV: Secura Bio, Inc.; 2021 Sept.59042 - Cresemba (isavuconazonium) package insert. Northbrook, IL: Astellas Pharma US, Inc; 2022 Feb.59321 - CredibleMeds. QT drug lists. Available on the World Wide Web at http://www.crediblemeds.org.59322 - Howes LG. Cardiovascular effects of drugs used to treat alzheimer's disease. Drug Saf. 2014;37:391–395.59809 - Mamiya K, Sadanaga T, Sekita A, et al. Lithium concentration correlates with QTc in patients with psychosis. J Electrocardiol 2005;38:148-51.59810 - van Noord C, Straus SM, Sturkenboom MC, et al. Psychotropic drugs associated with corrected QT interval prolongation. J Clin Psychopharmacol 2009;29:9-15.59811 - Altinbas K, Guloksuz S, Caglar IM, et al. Electrocardiography changes in bipolar patients during long-term lithium monotherapy. Gen Hosp Psychiatry 2014;36:694-7.59891 - Orkambi (lumacaftor; ivacaftor) tablet package insert. Boston, MA: Vertex Pharmaceuticals, Inc. 2022 Sept60001 - Daklinza (daclatasvir) package insert. Princeton, NJ: Bristol-Myers Squibb Company; 2019 Oct.60087 - Sprycel (dasatinib) tablet package insert. Princeton, NJ Bristol-Myers Squibb Company; 2021 June.60142 - Varubi (rolapitant) package insert. Waltham, MA: Tesaro Inc; 2018 April.60270 - Belbuca (buprenorphine) buccal film package insert. BioDeliviery Sciences International, Inc.: Raleigh, NC; 2022 June.60297 - Tagrisso (osimertinib) tablet package insert. Wilmington, DE: AstraZeneca Pharmaceuticals LP; 2022 Oct.60523 - Zepatier (elbasvir; grazoprevir) tablet package insert. Whitehouse Station, NJ: Merck, Inc; 2021 Dec.60634 - Oxaydo (oxycodone) immediate release tablets. Wayne, PA: Zyla Life Sciences US, Inc.; 2021 Mar.60748 - Nuplazid (pimavanserin) package insert. San Diego, CA: Acadia; 2020 Nov.60833 - Probuphine (buprenorphine) implant package insert. South San Francisco, CA: Titan Pharmaceuticals, Inc.; 2021 Mar.60864 - US Food and Drug Administration (FDA). FDA Drug Safety Communication: FDA warns about serious heart problems with high doses of the antidiarrheal medicine loperamide (Imodium), including from abuse and misuse. Retrieved June 7, 2016. Available on the World Wide Web at: http://www.fda.gov/Drugs/DrugSafety/ucm504617.htm?source=govdelivery&utm_medium=email&utm_source=govdelivery60958 - Levorphanol tablet package insert. Solana Beach, CA: Sentynl Therapeutics, Inc.; 2021 Jan.61077 - Sustol (granisetron) extended-release injection package insert. Redwood City, CA: Heron Therapeutics; 2016 Aug.61107 - Troxyca ER (oxycodone hydrochloride; naltrexone hydrochloride) extended-release capsules package insert. New York, NY: Pfizer, Inc.; 2016 Dec.61816 - Kisqali (ribociclib) tablets package insert. East Hanover, NJ: Novartis Pharmaceuticals Corporation; 2021 Sept.61845 - Austedo (deutetrabenazine) tablets package insert. Parsippany, NJ: Teva Neuroscience, Inc.; 2022 May.61870 - Chiu MH, Al-Majed NS, Stubbins R, et al. A case report of QT prolongation with glycopyrronium bromide in a patient with chronic tamoxifen use. BMC Res Notes. 2016;9:310.61871 - Slovacek L, Priester P, Petera J, et al. Tamoxifen/norfloxacin interaction leading to QT interval prolongation in a female patient with extracranial meningioma. Bratisl Lek Listy. 2011;112(6):353-4.61872 - Slovacek L, Ansorgova V, Macingova Z, et al. Tamoxifen-induced QT interval prolongation. J Clin Pharm Ther. 2008;33(4):453-5.61906 - Rydapt (midostaurin) capsule package insert. East Hanover,NJ: Novartis Pharmaceuticals Corporation; 2021 Nov.62131 - Vosevi (sofosbuvir; velpatasvir; voxilaprevir) tablet package insert. Foster City, CA: Gilead Sciences, Inc; 2019 Nov.62201 - Mavyret (glecaprevir; pibrentasvir) tablets package insert. North Chicago, IL: AbbVie Inc.; 2021 Sept.62245 - Besponsa (inotuzumab ozogamicin) injection package insert. Philadelphia, PA: Wyeth Pharmaceuticals Inc; 2017 Aug.62292 - Mylotarg (gemtuzumab ozogamicin) injection package insert. Philadelphia, PA: Pfizer Inc.; 2020 Feb.62649 - Sublocade (buprenorphine extended-release injection) package insert. North Chesterfield, VA: Indivior, Inc.; 2022 Aug.62723 - Macrilen (macimorelin) package insert. Frankfurt am Main, Germany: Aeterna Zentaris GmbH; 2018 Jan.62889 - Apadaz (benzhydrocodone; acetaminophen) tablets package insert. Newton, PA: KVK-Tech, Inc.; 2021 Mar.63161 - Lucemyra (lofexidine) tablets package insert. Louisville, KY: US WorldMeds, LLC; 2018 May.63317 - Braftovi (encorafenib) capsules package insert. Boulder, CO: Array BioPharma Inc.; 2022 Feb.63368 - Tibsovo (ivosidenib) tablet package insert. Cambridge, MA: Agios Pharmaceuticals; 2022 May.63589 - Soltamox (tamoxifen) oral solution package insert. Raleigh, NC: Midatech Pharma US Inc.; 2019 April.63777 - Daurismo (glasdegib) tablets package insert. New York, NY: Pfizer Labs; 2020 Mar.63787 - Xospata (gilteritinib) tablets package insert. Northbrook, IL: Astellas Pharma US, Inc.; 2022 Jan.63936 - Lamprene (clofazimine) package insert. East Hanover, NJ: Novartis Pharmaceuticals Corporation; 2019 Jan.63962 - Egaten (triclabendazole) package insert. East Hanover, NJ: Novartis Pharmaceuticals; 2022 Feb.64031 - Mayzent (siponimod) tablets package insert. East Hanover, NJ: Novartis Pharmaceutical Corporation; 2023 Jan.64391 - Beach SR, Kostis WJ, Celano CM, et al. Meta-analysis of selective serotonin reuptake inhibitor-associated QTc prolongation. J Clin Psychiatry 2014;75:e441-e449.64562 - Wakix (pitolisant) tablets package insert. Plymouth Meeting, PA: Harmony Biosciences, LLC; 2022 Dec.64567 - Rozlytrek (entrectinib) package insert. South San Francisco, CA: Genentech Inc.; 2022 July64576 - Xenleta (lefamulin) package insert. Dublin, Ireland: Nabriva Therapeutics US, Inc.; 2021 Mar.64608 - Pentostam (sodium stibogluconate injection) package leaflet: Information for the healthcare professional. Middlesex, United Kingdom: GlaxoSmithKline UK; 2014 Feb.64685 - Reyvow (lasmiditan) tablets package insert. Indianapolis, IN: Eli Lilly and Company; 2022 Sep.64690 - Morphine sulfate injection package insert. Lake Zurich, IL: Fresenius Kabi; 2018 May.65068 - Barhemsys (amisulpride) package insert. Indianapolis, IN: Acacia Pharma Inc; 2021 May.65098 - Isturisa (osilodrostat) tablet package insert. Lebanon, NJ: Recordati Rare Disease, Inc.; 2020 Mar.65157 - CredibleMeds. COVID-19 experimental therapies and TdP risk. Available on the World Wide Web at http://https://crediblemeds.org/blog/covid-19-experimental-therapies-and-tdp-risk. Accessed March 23, 2020.65169 - Ozanimod (Zeposia) capsules package insert. Summit, NJ: Celgene Corporation; 2022 Sept.65170 - Giudicessi JR, Noseworthy PA, Friedman PA, Ackerman MJ. Urgent guidance for navigating and circumventing the QTc prolonging and torsadogenic potential of possible pharmacotherapies for COVID-19 [published online ahead of print, March 25, 2020]. Mayo Clin Proc 2020;95.65387 - Retevmo (selpercatinib) capsules package insert. Indianapolis, IN: Eli Lilly and Company; 2022 Sept.65634 - Fintepla (fenfluramine) oral solution package insert. Emeryville CA: Zogenix, Inc.; 2023 Jan.65666 - Rukobia (fostemsavir) package insert. Research Triangle Park, NC: ViiV Healthcare; 2022 Jan.65809 - Olinvyk (oliceridine) injection package insert. Chesterbrook, PA: Trevana, Inc. 2021 Mar.66183 - Orgovyx (relugolix) tablets package insert. Brisbane, CA: Myovant Sciences, Inc.; 2020 Dec.66336 - Lupkynis (voclosporin) capsules package insert. Rockville, MD: Aurinia Pharma U.S., Inc.; 2021 Jan.66527 - Ponvory (ponesimod) tablet package insert. Titusville, NJ: Janssen Pharmaceuticals, Inc.; 2021 Oct.66990 - Exkivity (mobocertinib) capsules package insert. Lexington, MA: Takeda Pharmaceuticals America, Inc.; 2021 Sept.67231 - Recorlev (levoketoconazole) package insert. Chicago, IL: Xeris Pharmaceuticals, Inc.; 2021 Dec.67427 - Vonjo (pacritinib) capsules package insert. Seattle, WA: CTI BioPharma Corp; 2022 Feb.68325 - Krazati (adagrasib) tablets package insert. San Diego, CA: Mirati Therapeutics, Inc.; 2022 Dec.

Monitoring Parameters

  • ECG
  • LFTs
  • serum electrolytes

US Drug Names

  • Zofran
  • Zofran in Dextrose
  • Zofran ODT
  • Zofran Solution
  • Zuplenz
;