Which drug is associated with torsades de pointes?

• A. Sotalol
• B. Lidocaine
• C. Verapamil
• D. Metoprolol

Answer: (A)

Torsades de pointes is a polymorphic ventricular tachycardia that occurs when the QT interval is prolonged, creating afterdepolarizations that can trigger irregular beats. Sotalol is a class III antiarrhythmic that blocks potassium channels and lengthens the QT interval, increasing the risk of torsades, especially with electrolyte disturbances or low heart rate. The other drugs listed do not notably prolong repolarization: lidocaine primarily acts on depolarized tissue and tends to have little effect on the QT; verapamil and metoprolol affect conduction and rate but do not significantly prolong the QT interval. Therefore, sotalol is the drug most associated with torsades de pointes.