Amiodarone

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General

Adult Dosing

  • V-fib/pulseless V-tach
    • Loading dose = 300mg IV bolus followed by 150mg bolus PRN
  • Stable V-tach or SVT
    • Loading dose = 150mg IV in 100mL D5W over 10min
      • Follow by infusion of 1mg/min x 6hr; 0.5mg/min thereafter

Pediatric Dosing

Special Populations

Indications

  • Ventricular and supraventricular arrhythmias
  • 1st line for pulseless V-tach/V-fib
  • Used for atrial arrhythmias in patients with decreased EF

Contraindications

  • Allergy to class/drug
  • Iodine or shellfish allergy
  • Pregnancy

Adverse Reactions

  • Bradycardia
  • Hypotension with older solvent-based formulation. Uncommon with newer aqueous formulation.
  • Prolonged QT
  • Thyrotoxicosis[1]
    • Between 5-20% of patients treated with amiodarone have thyrotoxicosis (higher in areas of iodine deficiency)
  • Iodine-induced hyperthyroidism
    • It is thought that the iodine load may unmask hyperthyroidism in patients with multinodular goiter and subclinical Graves’ disease
  • Drug-induced destructive thyroiditis
    • More commonly, the cytotoxic effects of amiodarone destroy thyroid cells, resulting in a release of preformed hormone.
  • Amiodarone Pulmonary Toxicity
  • Hyperpigmentation rash
    Amiodarone hyperpigmentation.jpg

Pharmacology

  • Half-life: 58 days
  • Metabolism: Liver extensively
  • Excretion: Bile primarily

Mechanism of Action

  • Class III - Inhibits potassium channels
    • Impairs SA and AV node conduction
    • Decreases automaticity
    • Prolongs refractory period in accessory pathways
  • Also has class I & II properties

See Also

References

  1. Rosen's 8th Edition