USMLE

Amiodarone

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Cardiovascular Drugs
  1. Beta Blockers
  2. ACE Inhibitors
  3. Angiotensin II Receptor Blockers (ARBs)
  4. Adenosine
  5. Atropine
  6. Amiodarone
  7. DHP Calcium Channel Blockers
  8. Non-DHP Calcium Channel Blockers
  9. Clonidine
  10. Clopidogrel
  11. Digoxin
  12. Dopamine
  13. Epinephrine
  14. Hydralazine
  15. Loop Diuretics
  16. Nitroglycerin
  17. Norepinephrine
  18. Spironolactone
  19. Statins
  20. Thiazide Diuretics

Summary

Amiodarone is a class III antiarrhythmic drug used to treat ventricular arrhythmias, specifically ventricular fibrillation and ventricular tachycardia. Amiodarone is most commonly used as part of ACLS protocol, but may be prescribed for patients with atrial fibrillation and a history of ventricular arrhythmias to take at home. Important side effects of amiodarone include pulmonary toxicity, QT prolongation, and hypothyroidism.

Key Points

  • Mechanism
    • Antiarrhythmic
      • Class III
      • Blocks potassium channels causing prolonged repolarization of the cardiac action potential. This slows down the heart rate, decreases peripheral vascular resistance, and causes vasodilation
    • Clinical Use
      • Arrhythmias
        • Ventricular arrhythmias
          • Ventricular tachycardia
            • Part of ACLS protocol
          • Ventricular fibrillation
            • Also part of ACLS protocol
          • Supraventricular tachycardia (SVT)
            • Off-label use
        • Atrial fibrillation
          • Common off-label use
          • Particularly atrial fibrillation with a rapid ventricular rate
    • SE and AR
      • Pulmonary toxicity
        • Dyspnea, cough, chest pain, rales/crackles
        • Can be fatal
      • QT interval prolongation
        • Can lead to Torsades de Pointes
        • Requires close cardiac monitoring in hospital setting
      • Hypothyroidism
        • Amiodarone has high iodine content, which directly affects the thyroid
      • Hypotension
      • Bradycardia
        • Teach patient to monitor pulse at home
      • Visual disturbances
        • Secondary to corneal microdeposits
        • Photophobia, visual halos
      • Dermatological effects
        • Photosensitivity
        • Blue man syndrome
          • A blue/gray discoloration of the skin
          • An uncommon adverse effect that may present with long-time use
      • Hepatotoxicity
        • May increase ALT and AST
      • Teratogenic
        • Pregnancy Risk Category D