Oral Nifedipine parallels IV hydralazine in lowering down BP in acute hypertensive emergency in pregnancy

Intravenous hydralazine and oral nifedipine both exhibit the same efficacy in lowering the blood pressure in acute hypertensive emergency of pregnancy reports the results of small randomized trial published online in journal American Journal of Obstetrics and Gynecology.

Incidence of acute-onset, severe systolic hypertension; severe diastolic hypertension; or both during the prenatal, intrapartum, or postpartum periods is on the rise. Statistics from Preeclampsia 

Foundation shows that ten million women develop preeclampsia each year around the world. Worldwide about 76,000 pregnant women die each year from preeclampsia and related hypertensive disorders. And, the number of babies who die from these disorders is thought to be on the order of 500,000 per annum.

This small double blind RCT enrolled 60 patients over a period of 10 months, who were ≥ 24 weeks of gestational age and presented with sustained increase in systolic blood pressure of ≥160 mm Hg or diastolic blood pressure of ≥110 mm Hg on more than 2 occasions, 30 minutes apart.

They were randomized to receive either IV hydralazine 5, 10, 10, and 10 mg and 4 placebo tablets or oral nifedipine 10 mg (maximum 4 doses) and intravenous saline injections every 20 minutes until the until till blood pressure was brought down to 150 mm Hg systolic and ≤100 mm Hg diastolic. 

If one treatment regimen was found ineffective, crossover treatment was given.

The researchers were looking primarily at time taken to bring down the blood pressure, as well as dosage, maternal and neonatal morbidity.

After analysis of data it was seen that the minimum time to bring down the B.P was nearly the same in both study arms (40 Minutes). Hydralazine was associated with significant vomiting while other perinatal and maternal outcomes were same in both the groups.

A 2016 systematic review and meta-analysis published in BJOG found oral nifedipine as efficacious and intravenous labetalol, especially in low resource settings and in scenarios where an IV line cannot be secured.

ACOG committee opinion No. 692 on Emergent Therapy for Acute-Onset, Severe Hypertension During Pregnancy and the Postpartum Period also recommends, “Although relatively less information currently exists for the use of calcium channel blockers for this clinical indication, the available evidence suggests that immediate release oral nifedipine also may be considered as a first-line therapy, particularly when intravenous access is not available.”