Effectiveness of nifedipine, labetalol, and hydralazine as emergency antihypertension in severe preeclampsia: a randomized control trial

Background : Preeclampsia is a highly prevalent disease among pregnant women. In the event of hypertensive emergency, nifedipine, labetalol, and hydralazine are assigned as first-line therapies in preeclampsia. Further studies are needed to compare the effectiveness of these drugs to find the most cost-effective drug with minimal side effects. This study aimed to compare the effectiveness of these drugs in lowering blood pressure during hypertensive emergencies in severe preeclampsia. Methods : 60 pregnant women with severe preeclampsia were recruited in this multiple centre double-blind randomized clinical trial from May 2021 to April 2022 in Indonesia. The patients were divided equally into three groups and treated with three doses of nifedipine, labetalol, and hydralazine, respectively within one hour with 20 minutes interval. The effectiveness was measured based on systolic and diastolic blood pressures, and mean arterial pressure (MAP). The observation was carried out until five hours post-third dose administration.   Results : The blood pressure was reduced significantly after the administration of the first to the third dose of each antihypertensive (p<0.05). A single dose administration, four, one, and three patients had 20% MAP reduction in nifedipine, labetalol, and hydralazine group. Three, seven, and one patient had a failure of reaching 20% MAP reduction even after receiving the third dose. The effectiveness of the drugs to achieve 20% reduction of MAP could be ranked as follows: nifedipine>labetalol>hydralazine (57.49%, 42.13%, and 40.87%, respectively) for single dose and hydralazine>nifedipine>labetalol (111.3%, 85.12%, and 90.04%, respectively) for triple dose. Conclusions : Nifedipine is the most effective drug to reduce the blood pressure when single dose administration is used, but requires more doses to further reduce the blood pressure. Hydralazine is the most effective when the drug administration is maxed up to three doses within 60 minutes with 20 minutes interval. Thai Clinical Trials Registry (TCTR): TCTR20221014007 (14/10/2022)