Amiodarone Dosing Guidelines

Introduction to Amiodarone Therapy

The initial intravenous loading dose of amiodarone is 5 mg/kg, which is approximately 300 mg for an average adult, administered over one hour, followed by a maintenance infusion 1, 2

For life-threatening arrhythmias, an initial bolus of 150 mg IV over 10 minutes may be administered 3
An alternative dosing strategy for ventricular and supraventricular arrhythmias is 5 mg/kg (approximately 300 mg) over one hour 1, 2
In cardiac arrest situations, the 5 mg/kg dose may be administered over 15 minutes and repeated after one hour 1, 2

The maintenance infusion rate is 1 mg/min for 6 hours (total of 360 mg) or 0.5 mg/min for 18 hours (total of 540 mg) 3
The maximum dose in the first 24 hours is 2.2 g 3

For ventricular arrhythmias, the oral loading dose is 800-1600 mg/day in divided doses until a total of 10 g is reached, followed by a maintenance dose of 200-400 mg/day 3, 4
For atrial fibrillation, the oral loading dose is 600-800 mg/day in divided doses until a total of 10 g is reached, followed by a maintenance dose of 200 mg/day 3, 4

Continuous cardiac monitoring is required during IV administration to detect bradycardia, AV block, and hypotension 3, 5
Blood pressure monitoring should be performed throughout the infusion 3
Baseline and serial ECGs should be performed to evaluate QT prolongation 5
Thyroid and liver function tests should be performed at the start and during loading 5

Absolute contraindications include severe bradycardia or second-/third-degree AV block without a pacemaker, severe liver dysfunction, and baseline QT prolongation with a history of torsades de pointes 5
The dose of digoxin should be reduced by 50% when co-administered with amiodarone 5
The dose of warfarin should be reduced when co-administered with amiodarone 5
Other medications that prolong the QT interval should be avoided without specialist consultation 3, 4

The oral dose after IV therapy is based on the duration of IV therapy, with doses ranging from 800-1600 mg/day for less than 1 week of IV therapy to 400 mg/day for more than 3 weeks of IV therapy 4