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Amiodarone (Pacerone, Cordarone, Nexterone)
Updated On: July 10, 2026
Minutes for antiarrhythmic effect after IV loading; full effect requires tissue loading over days.
Approximately 30 min – 3 hr after IV loading dose.
Variable; days to weeks due to extensive tissue accumulation. Elimination half-life 40–55 days.
ACLS use - Mainstay for shock-refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) during cardiac arrest; given as a 300 mg IV/IO push with a 150 mg repeat dose if needed.
Hemodynamic effects - Even slow IV boluses commonly cause hypotension and bradycardia from the polysorbate 80 vehicle and direct vasodilation; have phenylephrine and atropine ready, or use the aqueous Nexterone formulation when available.
QT prolongation - Prolongs the QT interval and can precipitate TdP, especially with hypokalemia, hypomagnesemia, or concurrent QT-prolonging drugs; correct electrolytes before and during use.
Pulmonary toxicity risk - High inspired oxygen in patients on chronic amiodarone has been associated with postoperative ARDS; titrate FiO2 to the lowest level that maintains adequate saturation.
Thyroid effects - Iodine load can precipitate hypo- or hyperthyroidism; review thyroid function and consider amiodarone-induced thyrotoxicosis (AIT) in patients with new tachyarrhythmias on chronic therapy.
Management of excessive effect - Treat hypotension with fluids and vasopressors, bradycardia with atropine or pacing; isoproterenol and magnesium for amiodarone-associated TdP; the drug's huge volume of distribution makes hemodialysis ineffective.
Drug Interactions - Inhibits CYP3A4, CYP2C9, and P-glycoprotein; potentiates warfarin, digoxin, statins, and many anesthetic agents; reduce doses of those drugs in patients on chronic amiodarone.
Pediatric Implications - Used for shock-refractory pVT/VF and refractory supraventricular tachycardia (SVT); dose 5 mg/kg IV/IO bolus (max 300 mg), may repeat to a total of 15 mg/kg/day. Hypotension and bradycardia are common; ensure secure large-bore or central IV access.
Obstetric Implications - Crosses the placenta and concentrates in fetal tissue; associated with neonatal hypothyroidism, growth restriction, and bradycardia. Reserve for life-threatening maternal arrhythmias when alternatives have failed. Excreted in breast milk; generally not recommended during lactation.
Absolute: severe sinus-node dysfunction with symptomatic bradycardia, second- or third-degree atrioventricular (AV) block without a pacemaker, cardiogenic shock.
Relative: known iodine allergy, baseline QT prolongation, severe hepatic impairment, severe pulmonary disease.
Caution: thyroid disease, electrolyte abnormalities (hypokalemia, hypomagnesemia), concurrent QT-prolonging drugs, frail elderly with limited cardiac reserve.
1 mg/min for 6 hr, then 0.5 mg/min for 18 hr (max ~2.2 g over 24 hr).
Class III antiarrhythmic that blocks potassium channels to prolong phase-3 repolarization and refractory period; also blocks sodium and calcium channels and has noncompetitive alpha- and beta-adrenergic blocking activity.
Hepatic; active metabolite desethylamiodarone.
Biliary.
Contains 37% iodine by weight; cross-reacts with iodine allergy and contributes to thyroid dysfunction.
PVC tubing leaches plasticizer with prolonged infusion; use non-PVC (polyolefin) tubing and an in-line filter for infusions longer than 2 hr.
Standard IV formulation contains polysorbate 80 and benzyl alcohol; the aqueous Nexterone formulation avoids these and produces less hypotension on bolus.
Highly lipophilic with a volume of distribution of roughly 60 L/kg; not removed by hemodialysis.