Two Dose Regimens of Nifedipine for Management of Preterm Labor: A Randomized Controlled Trial

Abstract

We compared two dose regimens of tocolytic oral nifedipine. Women with singleton pregnancies admitted in preterm labor (24 to 34 weeks) were randomized to high-dose (HD) nifedipine ( N = 49; 20 mg loading dose, repeated in 30 minutes, daily 120 to 160 mg slow-release nifedipine for 48 hours followed by 80 to 120 mg daily until 36 weeks) or low-dose (LD) nifedipine ( N = 53; 10 mg, up to four doses every 15 minutes, daily 60 to 80 mg slow-release nifedipine for 48 hours followed by 60 mg daily until 36 weeks). Uterine quiescence at 48 hours (primary outcome); delivery at 48 hours, 34 and 37 weeks; and recurrent preterm labor were similar. Gestational age at delivery was higher in HD (36.0 +/- 2.8 versus 34.7 +/- 3.7 weeks, P = 0.049). Rescue treatment was needed more in LD (24.5 versus 50.9%, odds ratio = 0.3; 95% confidence interval 0.1 to 0.7). Maternal adverse effects, birth weight, intensive care nursery admission, and composite neonatal morbidity were similar. However, neonatal mechanical ventilation was needed less and nursery stay was shorter in HD. HD nifedipine does not seem to have an advantage over LD in achieving uterine quiescence at 48 hours. Further studies should address the optimal dose and formulation of tocolytic nifedipine.

Effects of betamethasone on fetoplacental and maternal hemodynamics in preterm pregnancies

“…No participant received maintenance tocolysis therapy when uterine contractions ceased. The loading dose of nifedipine (Nidilat; Sanofi Aventis, Istanbul, Turkey) was administered as a 10‐mg oral capsule every 15 minutes within the first hour . Maternal pulse and blood pressure were monitored after each capsule was administered.…”

“…The present prospective, self-controlled observational study was per- was administered as a 10-mg oral capsule every 15 minutes within the first hour. 10 Maternal pulse and blood pressure were monitored after each capsule was administered. Betamethasone (Celestone Cronodose; Schering-Plough, Istanbul, Turkey) was administered as two intramuscular doses of 12 mg each, administered 24 hours apart.…”

Calcium Channel Blockers as Tocolytics: Principles of Their Actions, Adverse Effects and Therapeutic Combinations

“…The appropriate dose of nifedipine for tocolysis is still under investigation. In a comparison of two dose regimens of oral nifedipine in a study on threatening PTB between gestational weeks 24 and 34, it was found that a high dose of the drug (20 mg loading dose, daily 120–160 mg for 48 hours, followed by 80–120 mg daily up to 36 weeks) did not have any advantage over a low dose (10 mg loading dose, daily 60–80 mg for 48 hours, followed by 60 mg daily up to 36 weeks) as regards uterine quiescence [34]. In a small Bulgarian study, nifedipine (40 mg four times daily) delayed a large majority of the pregnancies (32 out of 41) with early contractions until normal term, without significant side-effects [35].…”

Calcium Channel Blockers for the Management of Preterm Birth: A Review

“…One randomized controlled trial evaluated the difference between two dose protocols of tocolytic oral nifedipine. 73 One hundred two women were randomized to receive one of two regimens, the high-dose or the low-dose oral nifedipine. In the high-dose group, women were given a loading dose of 20 mg of crushed nifedipine sublingually, and in case uterine activity persisted, another equal loading dose was given after 30 minutes.…”