August 07, 2019
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Oral nifedipine, methyldopa, labetalol ‘viable initial options’ for severe hypertension in pregnancy in low-resource settings

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Comparison of the safety and efficacy of three oral antihypertensives — labetalol, nifedipine retard and methyldopa — for use in pregnant women with severe hypertension showed that each drug resulted in BP control within 6 hours, with nifedipine retard demonstrating the greatest frequency of BP control, according to data published in The Lancet.

Although typical hypertension treatments include IV medications, it may not always be a feasible method for drug delivery in pregnant women due to venous access and fetal monitoring in busy or low-income environments; therefore, oral drugs could prove to be as effective and more accessible for patients living in areas affected by these treatment disparities, according to the researchers.

Cardiology Today corresponded with Hillary Bracken, PhD, senior director at Gynuity Health Projects, regarding the implications of these findings.

“Use of oral antihypertensive agents in a structured, goal-oriented approach can effectively and safely control blood pressure in pregnant women with severe hypertension,” Bracken said. “Treatment can be initiated immediately upon diagnosis — particularly in limited resource medical environments. Initiation of therapy need not be delayed until transfer to a higher-level center and may be expected to reduce maternal morbidity.”

In the multicenter, parallel-group, open-label, randomized, controlled trial, researchers compared the safety and efficacy of nifedipine, labetalol and methyldopa at two public hospitals in Nagpur, India. Treatment eligible patients (n = 894) were aged at least 18 years, pregnant with fetuses gestated at least 28 weeks, required pharmacological BP control for severe hypertension and were able to swallow oral medication.

Women with severe hypertension were randomly assigned to receive one of the three drugs: 298 received nifedipine, 295 received labetalol and 301 received methyldopa. Treatment was initiated between April 1, 2015, and Aug. 21, 2017. The primary outcome was BP control, defined as 120 to 150 mm Hg systolic BP and 70 to 100 mm Hg diastolic BP within 6 hours, with no adverse events.

Researchers found that the primary outcome was more common in pregnant women who received nifedipine retard compared with those who received methyldopa (84% vs. 76%; P = .03). There was no difference in the primary outcome between the nifedipine and labetalol groups (84% vs. 77%; P = .05) and the labetalol and methyldopa groups (P = .8).

“We anticipated a significant level of maternal complications. [We] were surprised to find very low rates of maternal morbidity in each arm, including a single eclamptic seizure despite a low rate of magnesium sulfate (MgSO4) utilization.,” Bracken said. “[Additionally], we were surprised to find a higher rate of NICU utilization in the nifedipine arm despite equivalent birth weights and gestational ages.”

According to the results, seven (1% of births) adverse events occurred during the course of the study. One woman in the labetalol group had an intrapartum seizure and six neonates (one in the nifedipine group, two in the labetalol group and three in the methyldopa group) were stillborn.

“[Intensive] care unit admissions were significantly more frequent in the nifedipine group,” the authors wrote. “More neonates born to women in the nifedipine group were admitted to the intensive care unit because they had a low or very low birthweight compared with those born to women in the methyldopa or labetalol groups.”

“Infants in all groups were exposed to comparable prematurity,” Thomas Easterling, MD, director of the maternal hypertension clinic at the University of Washington School of Medicine, told Cardiology Today. “Birth weights and gestational ages at birth were not different between groups.  More babies in the nifedipine group required admission for their low birth weight, their admitting diagnosis.  It seems that in a more or less equivalent cohort, the small babies in the nifedipine group received more attention.”

These findings have implications in low-resource settings, as use of the oral antihypertensives studied is common and recommended by the WHO for treatment of severe hypertension in pregnancy.

“In low-resource settings, including some basic obstetrical facilities in the United States, oral treatment of severe hypertension in pregnancy can be initiated immediately, during triage for more definitive care,” Bracken told Cardiology Today. – by Scott Buzby

For more information:

Hillary Bracken, PhD, can be reached at Gynuity Health Projects, 220 East 42nd St., New York, NY 10017; email: hbracken@gynuity.org; Twitter: @Gynuity.

Disclosures: The study was funded by the University of British Columbia, Vancouver, and the Bill and Melinda Gates Foundation. Bracken reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.