====== Sotalol ====== Sotalol is a 1st-generation, nonselective beta-blocker with additional Class III antiarrhythmic properties. It blocks: • β1 receptors • β2 receptors • Cardiac potassium channels (IKr) Because of its potassium channel blockade, sotalol prolongs the QT interval. Classification: • 1st Generation (Nonselective) • Also a Class III Antiarrhythmic • No intrinsic sympathomimetic activity (ISA) → [[cardio:beta_blockers:start|Beta-Blockers Overview]] → [[cardio:arrhythmias:start|Dysrhythmias Module]] -------------------------------------------------------------------- ===== Mechanism of Action ===== Beta-blocking effects: • ↓ Heart rate • ↓ AV nodal conduction • ↓ Renin release Class III antiarrhythmic effects: • Blocks potassium channels • Prolongs action potential duration • Prolongs QT interval • Increases refractory period Net Effect: • Suppresses atrial and ventricular arrhythmias Unlike most beta-blockers, sotalol significantly prolongs QT. -------------------------------------------------------------------- ===== Indications ===== ==== Atrial Fibrillation / Atrial Flutter ==== • Rhythm control (not just rate control) ---- ==== Ventricular Arrhythmias ==== • Suppression of ventricular tachycardia ---- Sotalol is NOT commonly used for hypertension. -------------------------------------------------------------------- ===== Major Risk: Torsades de Pointes ===== Because sotalol prolongs QT: • Risk of torsades de pointes • Risk increases with: - Renal impairment - Electrolyte abnormalities - High doses Initiation often requires ECG monitoring. QT prolongation is dose-dependent. -------------------------------------------------------------------- ===== Pharmacokinetics ===== • Hydrophilic • Renally cleared • Minimal CNS penetration Dose adjustment required in renal impairment. -------------------------------------------------------------------- ===== Adverse Effects ===== Beta-blocker effects: • Bradycardia • Hypotension • Fatigue • Bronchospasm Class III effects: • QT prolongation • Torsades de pointes -------------------------------------------------------------------- ===== Contraindications ===== • Baseline prolonged QT • Severe bradycardia • High-grade AV block • Cardiogenic shock • Significant renal impairment • Hypokalemia or hypomagnesemia -------------------------------------------------------------------- ===== Sotalol vs Other Beta-Blockers ===== Most beta-blockers: • Do NOT prolong QT • Used for rate control Sotalol: • Used for rhythm control • Prolongs QT • Higher arrhythmia risk Compare with: • [[cardio:beta_blockers:metoprolol|Metoprolol]] (rate control) • [[cardio:beta_blockers:propranolol|Propranolol]] (nonselective, no QT effect) -------------------------------------------------------------------- ===== Sotalol vs Amiodarone ===== [[cardio:arrhythmias:amiodarone|Amiodarone]]: • Also Class III • More effective but more toxic Sotalol: • Cleaner systemic profile • Greater torsades risk -------------------------------------------------------------------- ===== Clinical Pearls ===== ✔ Nonselective beta-blocker + Class III antiarrhythmic ✔ Prolongs QT interval ✔ Risk of torsades de pointes ✔ Requires renal dose adjustment ✔ Used for rhythm control, not simple rate control -------------------------------------------------------------------- Related: → [[cardio:beta_blockers:start|Beta-Blockers Overview]] → [[cardio:arrhythmias:start|Dysrhythmias Module]] → [[cardio:intro:start|Return to Cardiovascular Modules]]