Overview
Sotalol is a class III antiarrhythmic agent with beta-blocking properties used to treat life-threatening ventricular arrhythmias and maintain normal sinus rhythm in patients with atrial fibrillation/flutter. It works by prolonging cardiac action potential duration and refractory periods while providing beta-adrenergic blockade. Due to its proarrhythmic potential, particularly torsade de pointes, it requires careful patient selection and monitoring.
Mechanism of Action
Sotalol has dual pharmacological actions: (1) Class III antiarrhythmic activity by blocking potassium channels, prolonging cardiac action potential duration and refractory periods, and (2) Class II beta-adrenergic blockade by competitively inhibiting beta-1 and beta-2 receptors, reducing heart rate and AV nodal conduction.
Indications
- Treatment of documented life-threatening ventricular arrhythmias
- Maintenance of normal sinus rhythm in patients with symptomatic atrial fibrillation/flutter
Common Doses
- 80 mg
- 120 mg
- 160 mg
- 240 mg
Dosage
Initiation requires hospitalization with continuous ECG monitoring. Typical starting dose is 80 mg twice daily, titrated gradually to 120-160 mg twice daily based on therapeutic response and QT interval monitoring. Dose adjustments required for renal impairment.
Black Box Warning
Black Box Warning: Proarrhythmic effects, particularly torsade de pointes
Contraindications
- Sinus bradycardia
- Sick sinus syndrome
- Second and third degree AV block without functioning pacemaker
- Congenital or acquired long QT syndromes
- Cardiogenic shock or decompensated heart failure
- Serum potassium <4.0 mEq/L
- Baseline QTc >450 msec
Side Effects
- Bradycardia
- Fatigue
- Dizziness
- Dyspnea
- Proarrhythmia (torsade de pointes)
- Heart failure exacerbation
- Hypotension
- Bronchospasm
- Hypoglycemia
Interactions
- Other QT-prolonging drugs (antiarrhythmics, antipsychotics, antibiotics)
- Calcium channel blockers (additive bradycardia)
- Digoxin (increased risk of bradycardia)
- Insulin and oral hypoglycemics (masked hypoglycemia symptoms)
- Beta-2 agonists (antagonized bronchodilation)
Counseling Points
- Take exactly as prescribed, usually twice daily
- Do not stop abruptly without medical supervision
- Report dizziness, fainting, palpitations, or shortness of breath immediately
- Monitor pulse regularly as instructed
- Maintain adequate potassium intake
- Inform all healthcare providers about sotalol use
- Avoid alcohol and other medications without consulting provider