cardio:beta_blockers:sotalol []

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====== 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]]

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===== 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.

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===== Indications =====

==== Atrial Fibrillation / Atrial Flutter ====

• Rhythm control (not just rate control)

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==== Ventricular Arrhythmias ====

• Suppression of ventricular tachycardia

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Sotalol is NOT commonly used for hypertension.

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===== 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.

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===== Pharmacokinetics =====

• Hydrophilic
• Renally cleared
• Minimal CNS penetration

Dose adjustment required in renal impairment.

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===== Adverse Effects =====

Beta-blocker effects:

• Bradycardia
• Hypotension
• Fatigue
• Bronchospasm

Class III effects:

• QT prolongation
• Torsades de pointes

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===== Contraindications =====

• Baseline prolonged QT
• Severe bradycardia
• High-grade AV block
• Cardiogenic shock
• Significant renal impairment
• Hypokalemia or hypomagnesemia

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===== 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)

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===== Sotalol vs Amiodarone =====

[[cardio:arrhythmias:amiodarone|Amiodarone]]:
• Also Class III
• More effective but more toxic

Sotalol:
• Cleaner systemic profile
• Greater torsades risk

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===== 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  

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Related:

→ [[cardio:beta_blockers:start|Beta-Blockers Overview]]
→ [[cardio:arrhythmias:start|Dysrhythmias Module]]
→ [[cardio:intro:start|Return to Cardiovascular Modules]]