What is the role of nifedipine in the treatment of preterm labor?

Updated: Dec 17, 2018
  • Author: Michael G Ross, MD, MPH; Chief Editor: Carl V Smith, MD  more...
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Answer

Nifedipine, a calcium channel blocker, is commonly used to treat high blood pressure and heart disease because of its ability to inhibit contractility in smooth muscle cells by reducing calcium influx into cells. Consequently, nifedipine has emerged as an effective and safe alternative tocolytic agent for the management of preterm labor. Despite its unlabeled status, several randomized studies have shown that the use of nifedipine in comparison with other tocolytics is associated with a more frequent successful prolongation of pregnancy, resulting in significantly fewer admissions of newborns to the neonatal intensive care unit, and may be associated with a lower incidence of RDS, necrotizing enterocolitis, and intraventricular hemorrhage.

A systemic review by Conde-Aqudelo found that nifedipine was associated with significantly fewer maternal adverse events than β2 -adrenergic-receptor agonists and magnesium sulfate for tocolysis in women with preterm labor. [34]

A recommended initial dosage of nifedipine is 20 mg orally, followed by 20 mg orally after 30 minutes. If contractions persist, therapy can be continued with 20 mg orally every 3-8 hours for 48-72 hours with a maximum dose of 160 mg/d. After 72 hours, if maintenance is still required, long-acting nifedipine 30-60 mg daily can be used.

Contraindications of nifedipine therapy include allergy to nifedipine, hypotension, hepatic dysfunction, concurrent use of beta-mimetics or MgSO4, transdermal nitrates, or other antihypertensive medication. Other commonly reported side effects of nifedipine are maternal tachycardia, palpitations, flushing, headaches, dizziness, and nausea. Continuous monitoring of the fetal heart rate is recommended as long as the patient has contractions; the patient's pulse and blood pressure should be carefully monitored. Pregnant women with liver disease should not be prescribed nifedipine.


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