Amiodarone

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)
  • Then 0.5 mg/min drip over next 18 hrs (540 mg total)
  • Oral dosage after IV infusion is 400 -800 mg PO daily

Special Populations

• Pregnancy Rating: D
• Lactation Risk Categories: Unsafe
• Renal Dosing- no adjustment
  • Adult
  • Pediatric
• Hepatic Dosing- caution and consider dose decrease
  • Adult
  • Pediatric

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

Amiodarone Adverse Effects

• Bradycardia
• Hypotension with older solvent-based formulation. Uncommon with newer aqueous formulation.
• 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.
• Amiodarone pulmonary toxicity
• Hyperpigmentation rash
  

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

• Critical care quick reference
• Amiodarone pulmonary toxicity