← Search & browse all drugs
CARDIOVASCULAR SYSTEM › CARDIAC THERAPY › ANTIARRHYTHMICS, CLASS I AND III › Antiarrhythmics, class III
amiodarone
C01BD01
Forms & Strengths
- Oral Tablet: 100 mg, 200 mg, 400 mg
- Intravenous Injection: 50 mg/mL
Adult Dosing
- Ventricular Fibrillation/Pulseless VT (IV): 300 mg rapid IV push; may follow with 150 mg in 3 to 5 minutes
- Recurrent Ventricular Arrhythmias (IV infusion): 150 mg over 10 minutes (15 mg/min), then 1 mg/min for 6 hours, then 0.5 mg/min maintenance
- Oral Maintenance/Loading: Load 800-1600 mg/day for 1-3 weeks, then reduce to 600-800 mg/day for 1 month, then maintenance 200-400 mg/daily
Pediatric Dosing
- Cardiac Arrest / VF / Pulseless VT (IV/IO): 5 mg/kg rapid IV/IO push, may repeat up to total 15 mg/kg (max 300 mg per dose)
- Refractory Arrhythmias (IV infusion): Loading dose 5 mg/kg IV over 20-60 minutes, then maintenance 5 mcg/kg/min up to 15 mcg/kg/min
- Oral (off-label): Load 10-15 mg/kg/day (or 600-800 mg/1.73 m2) divided BID for 4-14 days, then 5 mg/kg/day for several weeks
Indications
- Resuscitation of pulseless ventricular tachycardia and ventricular fibrillation refractory to defibrillation
- Treatment and prophylaxis of recurrent hemodynamically unstable ventricular tachycardia
- Maintenance of normal sinus rhythm in patients with symptomatic atrial fibrillation (off-label/guideline supported)
Mechanism of Action
- Class III antiarrhythmic agent that prolongs action potential duration and effective refractory period
- Blocks potassium channels (primary effect), sodium channels, and calcium channels
- Exerts non-competitive alpha and beta-adrenergic blocking properties
Contraindications
- Known hypersensitivity to amiodarone or iodine
- Severe sinus node dysfunction causing marked sinus bradycardia
- Second- or third-degree atrioventricular block without a functioning pacemaker
- Cardiogenic shock
Adverse Reactions
- Pulmonary toxicity including pneumonitis, pulmonary fibrosis, and ARDS
- Thyroid dysfunction (both hypothyroidism and hyperthyroidism)
- Hepatotoxicity with elevated serum transaminases
- Ocular effects including corneal microdeposits and optic neuropathy
- Cardiovascular effects including bradycardia, heart block, and hypotension
- Dermatological reactions including photosensitivity and slate-blue skin discoloration
Drug Interactions
- Inhibits CYP3A4, CYP2C9, and P-glycoprotein, increasing levels of statins, digoxin, and warfarin
- Co-administration with CYP3A4 inducers (e.g., rifampin, St. John's wort) decreases amiodarone serum concentrations
- Concomitant use with beta-blockers, calcium channel blockers, or other QT-prolonging agents increases risk of severe bradycardia and Torsades de Pointes
Curated Content: Needs Vetting Before Put to Clinical Use