Eclampsia Prophylaxis — RACP Adult Medicine MCQ

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EasyEmergency MedicineEclampsia ProphylaxisRACP Adult Medicine

A 30-year-old woman presents with severe pre-eclampsia at 32 weeks gestation. Her BP is 170/110 mmHg. She develops headache, visual disturbance, and hyperreflexia suggesting imminent eclampsia. What is the first-line agent for seizure prophylaxis?

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Correct answer: E — Magnesium sulfate

IV magnesium sulfate is the first-line agent for prevention (MAGPIE trial) and treatment of eclamptic seizures. Loading dose is 4 g IV over 20 minutes followed by 1 g/hr infusion for 24 hours. It is superior to diazepam and phenytoin for both prevention and recurrence of seizures. Monitor for toxicity: loss of patellar reflexes (early sign), respiratory depression (late), and cardiac arrest. Serum magnesium levels should be monitored. Calcium gluconate is the antidote for magnesium toxicity. Definitive treatment of pre-eclampsia is delivery.

Reference: eTG – 2025 – Obstetrics; SOMANZ – 2023 – Hypertension in Pregnancy Guidelines