Amiodarone

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General

  • Type: Antiarrhythmics
  • Dosage Forms: injectable solution, tablet
  • Routes of Administration: IV, PO
  • Common Trade Names: Cordarone, Pacerone, Nexterone

Adult Dosing

V-fib/pulseless V-tach

  • Loading dose = 300mg IV bolus followed by 150mg bolus PRN

Stable wide complex tachycardia (e.g. V-tach) or SVT

  • 150 mg in 100mL D5W over 10min (15 mg/min), followed by 1 mg/min drip over 6hrs (360 mg total)[1]
    • Then 0.5 mg/min drip over next 18 hrs (540 mg total)
    • Oral dosage after IV infusion is 400 -800 mg PO daily

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[2]
    • 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. Amiodarone. GlobalRPH. http://www.globalrph.com/amiodarone_dilution.htm.
  2. Rosen's 8th Edition