USMLE

Class III Antiarrythmics - Sotalol

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Cardiovascular Pharm
  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

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