What is the dose and purpose of magnesium sulfate in managing preeclampsia/eclampsia?

• A. 2–3 g IV daily to treat hypertension.
• B. 10–12 g IV bolus for analgesia.
• C. 1 g IV every 6 hours for cramps.
• D. 4–6 g IV loading dose, followed by 1–2 g/hour infusion to prevent seizures.

Answer: (D)

Magnesium sulfate is used to prevent seizures in preeclampsia and to treat eclamptic seizures. The standard approach starts with a loading dose of 4–6 g given intravenously, then continues with an infusion of 1–2 g per hour to maintain therapeutic levels and provide ongoing anticonvulsant protection. This regimen targets the CNS and neuromuscular excitability to reduce the risk of seizures during the high-risk period.

This isn't about lowering blood pressure, providing analgesia, or treating cramps, so the other dosing options don’t fit the purpose. Monitor for signs of toxicity—depressed reflexes, slowed respiration, or reduced urine output—and have calcium gluconate ready to treat any toxicity if it occurs.