Clonidine versus Captopril for Severe Postpartum Hypertension: A Randomized Controlled Trial

Abstract

Background: Changes during the puerperium are still unclear, particularly in women with hypertension. The choice of antihypertensives, both to control very high blood pressure episodes and to keep blood pressure stable, also requires further elucidation. Currently, there are no clear data to guide the decision for the choice of postpartum antihypertensives. Captopril plays an important role in the treatment of very high blood pressure episodes and may be used postpartum. Clonidine has been used as an alternative in pregnant or postpartum women with contraindications to captopril, with satisfactory effect. The objective of the present study was to evaluate the effectiveness and safety of clonidine compared to captopril for treating severe postpartum hypertension.

Methods and findings: A randomized, drug-controlled, triple-blind clinical trial evaluating postpartum women receiving captopril or clonidine. Inclusion criteria consisted of: women with hypertensive disorders of pregnancy systolic blood pressure (SBP) ≥180 mmHg and/or diastolic blood pressure (DBP) ≥110 mmHg], requiring magnesium sulfate. Exclusion criteria were: heart disease, smoking, illicit drug use, contraindications to captopril, clonidine or oral medication, and having used captopril/clonidine previously. The primary outcome was the frequency of very high blood pressure episodes while in the obstetric intensive care unit. A total of 90 postpartum women met the study inclusion criteria, with 45 randomized to each group. There were fewer very high blood pressure episodes during hospitalization (2.1 ± 2.1 vs. 3.5 ± 4.7, p = 0.08), greater percentage reduction in SBP (14.0% ± 8.6% vs. 10.8% ± 8.8%, p = 0.08) and fewer women requiring sodium nitroprusside (2.3% vs. 13.3%; RR: 0.17; 95%CI: 0.02-1.39; p = 0.06) in the clonidine group compared to the captopril group; however, these differences were not significant. The groups were similar regarding daily mean SBP or DBP; however, on the third postpartum day, mean SBP was lower in the clonidine compared to the captopril group (151.9 ± 11.8 mmHg vs. 158.1 ± 13.6 mmHg, p = 0.02). Although not statistically significant, adverse reactions were more common in the captopril group (28.8%) compared to the clonidine group (18.6%).

Conclusion: Clonidine and captopril represent safe, effective treatments for severe postpartum hypertension.

Trial registration: clinicaltrials.gov: www.clinicaltrial.gov, NCT01761916.

Fig 1. Procedures for the selection and follow-up of participants (CONSORT flow chart).

Fig 2. Mean systolic blood pressure according to hospitalization day.

Fig 3. Mean diastolic blood pressure according to hospitalization day.