The antidote for Torsades de Pointes is

• A. Calcium gluconate.
• B. Magnesium sulfate.
• C. Potassium chloride.
• D. Sodium bicarbonate.

Answer: (B)

Torsades de Pointes is driven by a prolonged QT interval that allows early afterdepolarizations to trigger a dangerous, twisting form of ventricular tachycardia. Magnesium sulfate works by stabilizing cardiac cell membranes and suppressing these abnormal afterdepolarizations, which helps prevent and terminate the TdP episode. It’s effective even if serum magnesium is not low, which is why it’s the first-line antidote in this situation. In practice, administer IV magnesium sulfate promptly (often 1–2 g IV push, with a possible subsequent infusion) and address underlying causes such as drug effect or electrolyte imbalances.

Calcium gluconate, potassium chloride, and sodium bicarbonate don’t directly target the mechanism of TdP. Calcium gluconate is used for calcium-related issues, potassium chloride addresses potassium disturbances, and sodium bicarbonate is not an effective treatment for TdP.