**Question:** The drug of choice for prevention of seizures in a patient with severe pre-eclampsia is:

A. Magnesium sulfate
B. Metformin
C. Indomethacin
D. Calcium channel blockers

**Correct Answer:** Magnesium sulfate

**Core Concept:** Pre-eclampsia is a complication of pregnancy characterized by hypertension and proteinuria after the 20th week of gestation. Seizures are a significant complication and Magnesium sulfate is the drug of choice for seizure prophylaxis in pre-eclampsia.

**Why the Correct Answer is Right:** Magnesium sulfate is a neuroprotective agent that works by blocking the N-methyl-D-aspartate (NMDA) receptors in the central nervous system, preventing excitotoxicity and reducing neuronal damage. It is effective in preventing seizures due to its anti-convulsant properties and has additional benefits such as reducing the risk of cerebral palsy in preterm infants, improving maternal cerebral blood flow, and decreasing the risk of maternal stroke.

**Why Each Wrong Option is Incorrect:**

A. Metformin: This is an anti-diabetic drug primarily used in type 2 diabetes mellitus, and is not indicated for seizure prophylaxis in pre-eclampsia.

B. Indomethacin: It is a nonsteroidal anti-inflammatory drug (NSAID) used for treating arthritis and other inflammatory conditions. It is not recommended for seizure prophylaxis in pre-eclampsia as it can worsen hypertension and renal dysfunction.

C. Calcium channel blockers: These drugs are used for hypertension and angina by blocking calcium channels, affecting cardiac and vascular smooth muscle function. They are not recommended for seizure prophylaxis in pre-eclampsia, as they may exacerbate hypertension and precipitate eclampsia (first episode of seizures in pregnancy).

**Clinical Pearl:** Pre-eclampsia is a medical emergency that requires prompt diagnosis and treatment to prevent maternal and fetal complications. Magnesium sulfate is the gold standard for seizure prophylaxis, while other options have either no effect or potential adverse effects. Close monitoring of serum magnesium levels is essential to avoid hypermagnesemia, which can cause respiratory depression, hypotension, and renal dysfunction.