Amiodarone Dosing for Arrhythmias

Intravenous Dosing for Acute/Life-Threatening Arrhythmias

For life-threatening ventricular arrhythmias, the American Family Physician recommends administering a 150 mg bolus over 10 minutes, followed by 1 mg/min for 6 hours, then 0.5 mg/min for 18 hours before transitioning to oral dosing 1, 2
The American Heart Association suggests using a central venous catheter whenever possible to minimize peripheral vein phlebitis, which occurs frequently with concentrations >2 mg/mL 3
Continuous ECG monitoring is mandatory for heart rate, AV conduction abnormalities, and QT prolongation during IV administration, with hypotension occurring in 16% of patients and bradycardia in 4.9% 3

For ventricular arrhythmias, the American Family Physician recommends an oral loading dose of 800-1,600 mg/day in divided doses until a total of 10 grams has been administered, followed by a maintenance dose of 200-400 mg/day 1, 2
For atrial fibrillation, the American Family Physician recommends an oral loading dose of 600-800 mg/day in divided doses until a total of 10 grams has been given, followed by a maintenance dose of 200 mg/day 1, 2
The American Heart Association recommends a standard loading dose of 400-600 mg daily in divided doses for 2-4 weeks, followed by a maintenance dose of 100-200 mg daily 4

When transitioning from IV to oral dosing, the conversion dose depends on the duration of IV therapy, with the American Family Physician recommending 800-1,600 mg oral amiodarone per day for IV duration <1 week 1, 2, 4
For IV duration 1-3 weeks, the American Family Physician recommends transitioning to 600-800 mg oral amiodarone per day 1, 2, 4
For IV duration >3 weeks, the American Family Physician recommends transitioning to 400 mg oral amiodarone per day 1, 2, 4

The American Heart Association suggests that dose reduction is essential for long-term therapy to minimize toxicity, with the dose kept at the lowest effective level 3
Amiodarone has an extremely long half-life averaging 58 days, and maximal antiarrhythmic effects are not attained before 90-150 days of treatment 3

Absolute contraindications to IV amiodarone include bradycardia or second/third-degree heart block without a pacemaker, according to the American Heart Association 3
Mandatory drug interaction adjustments include reducing digoxin dose by 50% when starting amiodarone, and reducing warfarin dose by one-third to one-half and monitoring INR at least weekly for the first 6 weeks 3

The American Heart Association recommends monitoring liver and thyroid function every 6 months during maintenance therapy, and watching for bradycardia, QT prolongation, hypotension, and heart block during loading 3, 4
Monitoring for pulmonary toxicity, thyroid dysfunction, and hepatic toxicity is also necessary during long-term therapy 4