Amiodarone

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

Contraindications

• Iodine or shellfish allergy
• Pregnancy

Indications

• Ventricular and supraventricular arrhythmias
• 1st line for pulseless V-tach/V-fib
• Used for atrial arrhythmias in pts w/ decr EF

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

Adverse Drug Rxns

• Bradycardia, hypotension
• Prolonged QT
• Thyrotoxicosis
  • 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.

See Also

• Antiarrhythmics
• Critical care quick reference