A 48-year-old pregnant woman (32 weeks gestation) presents with BP 168/108 mmHg, severe headache, and 24-hour proteinuria of 3.6 g. She has hyperreflexia and brisk ankle clonus. The antihypertensive of choice to prevent eclamptic seizures is:

• A IV diazepam
• B IV phenytoin
• C IV labetalol alone
• D IV magnesium sulfate ✓

Explanation

IV magnesium sulfate is the agent of choice for seizure prophylaxis and treatment in severe pre-eclampsia/eclampsia. The Magpie trial established magnesium's superiority over phenytoin and diazepam for preventing eclamptic seizures (50% reduction). Magnesium acts by antagonizing NMDA receptors in the cerebral cortex. Labetalol controls blood pressure but does not prevent seizures. Phenytoin and diazepam are inferior and not recommended as first-line prophylaxis. IV magnesium is continued for 24 hours postpartum.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.