Hydralazine (Maternal-Newborn) - CE/NCPD

The content in Clinical Skills is evidence based and intended to be a guide to clinical practice. Always follow your organization’s practice.

ALERT

Use caution when administering antihypertensive medications to a patient receiving magnesium sulfate. A rapid decrease in maternal blood pressure may compromise uteroplacental perfusion, precipitate maternal shock, or contribute to placental abruption.^{undefined#ref1">1,13}

Take steps to eliminate interruptions and distractions during medication preparation.

OVERVIEW

Hydralazine is used to treat blood pressure (BP) elevations that accompany hypertensive disorders of pregnancy. Hydralazine is a peripheral vasodilator that relaxes the arteriolar smooth muscle. Increases in heart rate, stroke volume, cardiac output, and left ventricular ejection fraction typically occur with hydralazine use. Hydralazine may be used for first-line management of acute-onset severe hypertension in pregnant and postpartum patients.⁴ The drug does not cross the placenta in a clinically significant degree.

Hydralazine is indicated for IV administration for severely elevated BP. Hydralazine is contraindicated in patients with documented hypersensitivity to the drug or any component of the formulation, coronary artery disease, or mitral valve rheumatic heart disease.⁶ Caution should be used when administering hydralazine to patients with severe renal impairment.⁶

Maternal vital signs and the fetal heart rate (FHR) pattern should be frequently monitored after hydralazine administration. The patient’s response to antihypertensive medication should be monitored closely if hypertensive disorders of pregnancy are present. Antihypertensive therapy should not decrease arterial pressure too significantly or too rapidly because uteroplacental perfusion may be compromised,^1,7 resulting in an interruption of fetal oxygenation with Category II (indeterminate) or Category III (abnormal) FHR characteristics.⁵ Treatment is indicated for systolic BP of 160 mm Hg or greater, diastolic BP of 110 mm Hg or greater, or both, confirmed as persistent (lasting 15 minutes or more).^1,4 Target range is systolic BP of 140 to 150 mm Hg and diastolic BP of 90 to 100 mm Hg.³

Common adverse reactions to hydralazine are headache, palpitations, tachycardia, and drug-induced lupus syndrome (Table 1).⁶ Other adverse reactions include dizziness, diarrhea, nausea, vomiting, edema, and peripheral neuropathy.⁶

When a secondary antihypertensive medication is given (e.g., nifedipine followed by labetalol or labetalol followed by hydralazine) and BP remains elevated, initiation of an emergency consultation from a specialist in maternal-fetal medicine, internal medicine, anesthesiology, or critical care is recommended.^1,2,3

If the patient or support person express concern regarding the accuracy of a medication, the medication should not be given. The concern should be explored, the practitioner notified, and the order verified.

SUPPLIES

See Supplies tab at the top of the page.

EDUCATION

• Provide developmentally and culturally appropriate education based on the desire for knowledge, readiness to learn, and overall neurologic and psychosocial state.
• Educate the patient and support person regarding the purpose of the medication and the mode of administration.
• Explain to the patient and support person the importance of managing medication information to identify and resolve discrepancies.¹²
• Instruct the patient and support person regarding the potential side effects and adverse reactions to the medication.
• Instruct the patient to ask for assistance when getting out of bed.
• Encourage questions and answer them as they arise.

ASSESSMENT AND PREPARATION

Assessment

1. Perform hand hygiene before patient contact. Don appropriate personal protective equipment (PPE) based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
2. Introduce yourself to the patient and support person.
3. Verify the correct patient using two identifiers.
4. Assess baseline vital signs (including BP).
5. Assess the patient’s medication history, including any drug allergies.
6. Assess the patient for specific contraindications to receiving hydralazine and advise the practitioner accordingly.
7. Assess FHR pattern and uterine activity using electronic fetal monitoring as appropriate for the clinical situation and per the organization’s practice.

Preparation

1. Verify the patient’s actual admission weight in kilograms. Reweigh the patient if appropriate.¹¹ Do not use stated, estimated, or historical weight.¹¹
2. Obtain the medication, check the practitioner’s order, verify the expiration date, and inspect the medication for particulates, discoloration, or other loss of integrity.

   Do not use medication that is cloudy or precipitated unless such is indicated by its manufacturer as being safe.

3. Review medication reference information pertinent to the medication’s action, purpose, onset of action and peak action, normal dose, and common side effects and implications.
4. Ensure that all appropriate antidotes, reversal agents, and rescue agents are readily available.¹¹

PROCEDURE

1. Perform hand hygiene and don gloves. Don additional PPE based on the patient’s need for isolation precautions or the risk of exposure to bodily fluids.
2. Verify the correct patient using two identifiers.
3. Explain the procedure to the patient and support person and ensure that the patient agrees to treatment.
4. Ensure the rights of medication safety.
5. Use commercially available or pharmacy-prepared prefilled syringes to flush and lock vascular access devices (VADs).⁹
6. Disinfect vials by cleansing the access diaphragm using friction and a sterile 70% isopropyl alcohol, ethyl alcohol, iodophor, or other approved antiseptic swab and allow to dry at least 10 seconds.¹⁰
7. Draw the prescribed amount of medication into the syringe and prepare the syringe for IV administration; read the medication label for a second check of correct name and dose against the medication administration record (MAR). If the medication is in a glass ampule, replace the filter straw with the appropriate-size needle for injection, if needed.

   Remove the ordered dose of medication from the vial using a syringe and needleless attachment immediately before administration. Hydralazine changes color after contact with metal; discard any discolored hydralazine solution.

8. Label all syringes of IV push medications or solutions unless the syringes are prepared at the patient’s bedside and the medication is immediately administered without any break in the process.¹⁰ Use bar code scanning or similar technology immediately before administration.¹⁰
9. Remove gloves, perform hand hygiene and don clean gloves.
10. If using a disinfecting port protector or cap, remove it from the needleless connector and discard.
11. Disinfect the connection surface and sides of the needleless connector using vigorous mechanical scrubbing for 5 to 15 seconds using 70% isopropyl alcohol or alcohol-based chlorhexidine suitable for use with medical devices.⁸ Allow the solution to dry.⁸
12. Confirm patency of the VAD by aspirating for blood return and flushing the VAD using a 10-ml syringe filled with preservative-free 0.9% sodium chloride solution.⁹ Use a minimum volume of solution that is equal to twice the internal volume of the catheter and add-on devices or a larger volume (e.g., 5 ml).⁹

    Rationale: A 10-ml syringe generates lower injection pressure.⁹

13. Administer IV push medication using an appropriate-size syringe for the required dose (i.e., a syringe smaller than 10 ml).⁹
14. Connect the syringe or insert the needleless adapter in the IV push port.
15. Administer the IV push medication within the amount of time recommended by the organization’s practice, the pharmacist, the medication reference manual, or the manufacturer.
16. Remove the syringe and discard it in the proper receptacle.

    Flush the VAD using a 10-ml syringe filled with preservative-free 0.9% sodium chloride solution.⁹ Use a minimum volume of solution that is equal to twice the internal volume of the catheter and add-on devices or a larger volume (e.g., 10 ml for central VADs; 5 ml for peripheral IV catheters).⁹

    Rationale: A 10-ml syringe generates lower injection pressure.⁹

17. Lock the catheter or resume the ordered infusion. Lock the catheter port with the appropriate solution per the manufacturer’s instructions.
18. If using a disinfecting port protector or cap, apply a new one.
19. Discard supplies, remove PPE, and perform hand hygiene.
20. Document the procedure in the patient’s record.

MONITORING AND CARE

1. Monitor the patient for adverse and allergic reactions to the medication. Recognize and immediately treat respiratory distress and circulatory collapse, which are signs of a severe anaphylactic reaction. Follow the organization’s practice for emergency response.
2. Monitor the patient’s BP during hydralazine therapy per the organization’s practice or:
   1. Monitor the patient’s BP 20 minutes after administration.²
   2. If additional doses of hydralazine are needed, assess the BP 20 minutes after each dose.^1,2
   3. When the desired BP threshold is achieved, repeat BP measurement every 10 minutes for 1 hour, then every 15 minutes for 1 hour, then every 30 minutes for 1 hour, then every hour for 4 hours.^1,2
3. Assess FHR pattern and uterine activity using electronic fetal monitoring as appropriate for the clinical situation and per the organization’s practice.
4. Institute fall risk precautions per the organization’s practice.

EXPECTED OUTCOMES

• Medication administered per the rights of medication safety
• Target BP achieved after medication administration
• No adverse reactions in the patient or fetus

UNEXPECTED OUTCOMES

• Medication not administered per the rights of medication safety
• Target BP not achieved or BP remains elevated after medication administration
• Adverse reactions in the patient or fetus

DOCUMENTATION

• Patient’s response to the medication, including any adverse reactions
• Medication administration
• Vital signs
• FHR pattern, (if indicated) including changes noted after administration
• IV injection site
• IV patency and primary fluid
• Education
• Unexpected outcomes and related interventions
• Patient’s weight in kilograms

REFERENCES

1. American College of Obstetricians and Gynecologists (ACOG). (2019). Practice bulletin no. 203: Chronic hypertension in pregnancy. Obstetrics & Gynecology, 133(1), e26-e50. doi:10.1097/AOG.0000000000003020 (Level I)
2. American College of Obstetricians and Gynecologists (ACOG). (2020). Safe motherhood initiative: Hydralazine algorithm. Retrieved November 30, 2023, from https://www.acog.org/-/media/project/acog/acogorg/files/forms/districts/smi-hypertension-bundle-hydralazine-algorithm.pdf (Level I)
3. American College of Obstetricians and Gynecologists (ACOG). (2020). Safe motherhood initiative: Maternal safety bundle for severe hypertension in pregnancy. Retrieved November 30, 2023, from https://www.acog.org/-/media/project/acog/acogorg/files/forms/districts/smi-hypertension-bundle-slides.pdf (Level I)
4. American College of Obstetricians and Gynecologists (ACOG) Committee on Clinical Practice Guidelines–Obstetrics. (2020, reaffirmed 2023). Practice bulletin no. 222: Gestational hypertension and preeclampsia. Obstetrics & Gynecology, 135(6), e237-e260. doi:10.1097/AOG.0000000000003891 (Level I)
5. Cashion, K. (2024). Chapter 18: Fetal assessment during labor. In D.L. Lowdermilk and others (Eds.), Maternity & women’s health care (13th ed., pp. 356-374). St. Louis: Elsevier.
6. Clinical Pharmacology powered by Clinical Key. (2013-2023). Hydralazine. Retrieved November 30, 2023, from https://www.clinicalkey.com
7. Dix, D. (2024). Chapter 27: Hypertensive disorders. In D.L. Lowdermilk and others (Eds.), Maternity & women’s health care (13th ed., pp. 585-599). St. Louis: Elsevier.
8. Infusion Nurses Society (INS). (2021). Infusion therapy standards of practice. Standard 36: Needleless connectors. Journal of Infusion Nursing, 44(Suppl. 1), S104-S107. (Level I)
9. Infusion Nurses Society (INS). (2021). Infusion therapy standards of practice. Standard 41: Flushing and locking. Journal of Infusion Nursing, 44(Suppl. 1), S113-S118. (Level I)
10. Institute for Safe Medication Practices (ISMP). (2015). ISMP safe practice guidelines for adult IV push medications: A compilation of safe practices from the ISMP Adult IV Push Medication Safety Summit. Retrieved November 30, 2023, from https://www.ismp.org/sites/default/files/attachments/2017-11/ISMP97-Guidelines-071415-3.%20FINAL.pdf (Level VII)
11. Institute for Safe Medication Practices (ISMP). (2022). 2022-2023 Targeted medication safety best practices for hospitals. Retrieved November 30, 2023, from https://www.ismp.org/guidelines/best-practices-hospitals (Level VII)
12. Joint Commission, The. (2024). National Patient Safety Goals for the hospital program. Retrieved November 30, 2023, from https://www.jointcommission.org/-/media/tjc/documents/standards/national-patient-safety-goals/2024/npsg_chapter_hap_jan2024.pdf (Level VII)
13. Ketcham, N. and others. (2023). Chapter 10: Complications of pregnancy. In S.S. Murray and others (Eds.), Foundations of maternal-newborn and women’s health nursing (8th ed., pp. 207-268). St. Louis: Elsevier.

ADDITIONAL READINGS

Druzin, M. and others. (2021). Improving health care response to hypertensive disorders of pregnancy: A California Maternal Quality Care Collaborative (CMQCC) quality improvement toolkit. Retrieved November 30, 2023, from https://www.cmqcc.org

Elsevier Skills Levels of Evidence

• Level I - Systematic review of all relevant randomized controlled trials
• Level II - At least one well-designed randomized controlled trial
• Level III - Well-designed controlled trials without randomization
• Level IV - Well-designed case-controlled or cohort studies
• Level V - Descriptive or qualitative studies
• Level VI - Single descriptive or qualitative study
• Level VII - Authority opinion or expert committee reports

Clinical Review: Aimee Hardt, MN, APRN, CNS, ACCNS-N

Published: January 2024