Which property uniquely distinguishes sotalol from all other clinically used beta-blockers?

• A It blocks both beta-1 and beta-2 receptors nonselectively
• B It possesses intrinsic sympathomimetic activity at the beta receptor
• C It undergoes complete first-pass hepatic metabolism
• D It blocks the delayed rectifier potassium current, prolonging action potential duration and QT interval ✓

Explanation

Sotalol combines nonselective beta-blockade with Class III activity: it inhibits IKr (rapid delayed rectifier potassium current), lengthening repolarization, action potential duration, and the QT interval. This makes it effective for ventricular arrhythmias and maintenance of sinus rhythm in atrial fibrillation but creates a dose-related torsades de pointes risk. Nonselective beta-blockade alone (option A) is shared with propranolol and nadolol. Its renal elimination means dose adjustment in kidney disease is essential.

Reference: Katzung's Basic and Clinical Pharmacology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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