Efficacy of nifedipine versus hydralazine in the management of severe hypertension in pregnancy: A randomised controlled trial

Abstract

Background: Despite the availability of effective antihypertensive drugs, the quality of evidence regarding the best antihypertensive agent for the treatment of hypertensive emergencies in pregnancy is still poor.

Aim: The aim of this study was to compare the efficacy and side effects of oral nifedipine and intravenous hydralazine for control of blood pressure (BP) in severe hypertension in pregnancy.

Materials and methods: An open-label, parallel, randomised, controlled trial of 78 pregnant women (≥28 weeks' gestation) with severe hypertension was conducted. Severe hypertension was defined as systolic BP of 160 mmHg or above and/or diastolic BP of 110 mmHg or above. They were randomly (1:1 ratio) administered oral nifedipine 20 mg or intravenous hydralazine 10 mg every 30 min up to 5 doses or until the target BP of 140-150 mmHg systolic and 90-100 mmHg diastolic was achieved. Intravenous labetalol was given if the primary treatment failed. The primary outcome measure was the number of doses needed to achieve targeted BP. The secondary outcome measures were the time needed to achieve desired BP, maternal adverse effects and perinatal outcome.

Results: The sociodemographic characteristics did not differ between the two study groups. The average number of dosages (nifedipine; 1.4 ± 0.6 vs. hydralazine; 1.7 ± 0.5, P = 0.008) needed to control the BP was lower in the nifedipine arm. Time (min) taken to control the BP was similar between the groups (hydralazine; 43.7 ± 19.7 vs. nifedipine; 51.2 ± 18.9, P = 0.113). Adverse maternal and perinatal effects did not differ in the study groups.

Conclusion: Oral nifedipine and intravenous hydralazine showed comparable efficacy in the BP control in the severe hypertensive disorders of pregnancy without significant difference in adverse maternal and perinatal outcomes. However, further studies are required to explore the role of these drugs in BP control during hypertensive emergencies in pregnancy.

Clinicaltrials.gov: (Identification number: NCT04435210).

Keywords: Hydralazine; nifedipine; pregnancy; severe hypertension.