A comparative evaluation of intravenous labetalol versus oral nifedipine for control of severe pregnancy-induced hypertension with low-dose regimen

Abstract

Background: Hypertensive disorders complicate 5%–10% of all pregnancies and contribute greatly to maternal morbidity and mortality rates. Dangerous hypertension can cause cerebrovascular hemorrhage, hypertensive encephalopathy, and can trigger eclamptic convulsions. Blood pressure (BP) ≥160/110 mmHg in pregnancy requires prompt treatment. Both nifedipine and intravenous (IV) labetalol are effective antihypertensive agents belonging to different pharmacological classes and with different mechanisms of action. This study compares both the drugs. Objective: To compare the efficacy and safety of oral nifedipine versus IV labetalol for control of BP in cases of severe pregnancy-induced hypertension (PIH) with low-dose regimen. Materials and Methods: Pregnant women aged 18–40 years admitted in obstetrics and gynecology department with severe PIH, that is, BP ≥160/110 mmHg were included in this randomized prospective study. Simple randomization was done. A total of 30 patients in group A were given 5 mg oral nifedipine, to be repeated after half an hour if target BP of 150/100 mmHg was not achieved. A total of 30 patients in group B were given IV labetalol 20 mg initially followed by doses of 20, 20, 40, 40, and 80 mg every 20 min, if target BP was not achieved (maximum dose not to exceed 220 mg). The primary outcome variable was time necessary to achieve target BP. The secondary outcome variables were number of doses, cost of drug, need of crossover treatment, and adverse maternal and fetal side effects. Result: Patients receiving oral nifedipine achieved the target BP in 43 ± 16.74 min as compared with 38.67 ± 19.43 min in labetalol group (p = 0.3589). This difference was not significant. No maternal or fetal side effects were observed in both the groups. Labetalol was the costlier drug. Conclusion: Both regimens were equally effective in management of severe PIH with respect to time taken to achieve target BP. The adverse events in mother and baby were also less in view of the lower doses of the two agents used. Oral nifedipine was significantly less costly whereas IV labetalol was preferred in patients who were unable to take drug orally as in immediate postoperative patients and patients with altered sensorium.