Oral nifedipine versus intravenous labetalol for acute blood pressure control in hypertensive emergencies of pregnancy: a randomised trial

Abstract

Objective: To compare oral nifedipine with intravenous labetalol in their rapidity to control hypertensive emergencies of pregnancy.

Design: A double-blind randomised trial.

Setting: A university hospital in Malaysia.

Population: Pregnant women with severe gestational hypertension≥160/110 mmHg who required immediate treatment.

Methods: Patients were randomised to receive nifedipine (10 mg tablet, orally, up to five doses) and intravenous placebo saline injection or intravenous labetalol injection (in an escalating dose regimen of 20, 40, 80, 80 and 80 mg) and a placebo tablet every 15 minutes until the target blood pressure of ≤150/100 mmHg was achieved. Crossover treatment was effected if the initial treatment regimen was unsuccessful. MAIN OUTCOME MEASURE The time taken to achieve a blood pressure of ≤150/100 mmHg.

Results: The median time taken to achieve target blood pressure was 30 minutes (interquartile range, IQR 22.5-67.5 minutes) versus 45 minutes (IQR 30-60 minutes) for nifedipine and labetalol, respectively (P=0.59). Repeated measures analysis of variance indicated that in the first hour both systolic (F=87.6, P<0.001) and diastolic (F=55.8, P<0.001) blood pressure significantly decreased, but there was no difference between the nifedipine and labetalol groups for both systolic (F=0.12, P=0.74) and diastolic (F=0.92, P=0.34) blood pressure trends over time. Crossover treatment was required in 20% of women from each group.

Conclusions: Oral nifedipine and intravenous labetalol regimens are similarly effective in the acute control of severe hypertension in pregnancy.