Medicine & USMLE

Class III Antiarrythmics - Sotalol

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Cardiovascular Pharm (Old)
  1. Adenosine
  2. Magnesium
  3. Nitroprusside
  4. Nitrates
  5. Ivabradine
  6. Digoxin/Digitalis
  7. Class IA Antiarrhythmics
  8. Class IB Antiarrhythmics
  9. Class IC Antiarrhythmics
  10. Class II Antiarrhythmics
  11. Class III Antiarrhythmics - Amiodarone
  12. Class III Antiarrythmics - Sotalol
  13. Class III Antiarrhythmics - Ibutilide, Dofetilide
  14. Class IV Antiarrhythmics - Verapamil, Diltiazem
  15. HMG-CoA Reductase Inhibitors (Statins)
  16. Ezetimibe
  17. Fibrates
  18. PCSK9 Inhibitors (Alirocumab, Evolocumab)
  19. Fish Oil and Omega-3s
  20. Milrinone
  21. Aliskiren
  22. Hydralazine
  23. Ranolazine
  24. Sacubitril

Class III Antiarrythmics - Sotalol

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Summary

Sotalol is Class III antiarrhythmic medication that works by blocking potassium channels in cardiomyocytes, which increases the refractory period. Sotalol primarily targets arrhythmias in non-nodal cardiac myocytes, which makes it good for rhythm control. Sotalol is also a beta blocker, and has mild class II antiarrhythmic properties. A dangerous side effect of sotalol and all class 3 antiarrhythmics is QT prolongation leading to Torsades de pointes.

Key Points

  • Sotalol
    • Mechanism
      • Acts as Class 2 and 3 Antiarrhythmic
        • Causes Beta-blocker Activity
          • Reduces cAMP and calcium influx at nodal tissue
          • Slows down heart rate, AV conduction (PR interval)
        • Blocks Potassium (K+) channels
          • Prolongs phase 3 repolarization by blocking potassium outflow, mainly in non-nodal tissue
          • Increases AP duration and effective refractory period (ERP)
            • Prolonged QT creates risk for early after-depolarizations and Torsades de Pointes
    • Clinical Use
      • Treats Atrial flutter/fibrillation
      • Treats Ventricular tachycardia
    • Adverse Effects
      • Causes Long QT (Torsades de Pointes risk)
        • All drugs that increase QT interval increase the risk of early after-depolarizations causing ventricular arrhythmias like Torsades de Pointes
        • Avoid in patients with congenital or acquired long QT syndrome