What is the recommended dosage for Cardarone (Amiodarone) tablets?

Cardarone (Amiodarone) Tablet Dosage

For oral amiodarone loading, use 600-800 mg per day in divided doses until a total of 10 grams is administered (typically 2-3 weeks), then reduce to a maintenance dose of 200-400 mg daily. 1

Loading Dose Regimens

The loading approach varies based on clinical setting and urgency:

Outpatient Loading

• 600-800 mg per day in divided doses until 10 grams total is reached, followed by 200-400 mg daily maintenance 1
• This regimen is appropriate for atrial fibrillation and less urgent ventricular arrhythmias 2
• The loading period typically spans 2-4 weeks 2

Inpatient Loading

• 1,200-1,800 mg per day in divided doses until 10 grams total, then 200-400 mg daily maintenance 1
• Alternative single-dose option: 30 mg/kg as a single dose 1
• Higher loading doses (up to 1,600 mg daily) may be used for ventricular arrhythmias in monitored settings 2
• Inpatient monitoring allows for closer surveillance of bradycardia, QT prolongation, and hypotension 2

Accelerated High-Dose Loading

• For refractory ventricular arrhythmias: 50 mg/kg per day for 3 days, then 30 mg/kg per day for 2 days, followed by 300-400 mg twice daily maintenance 3
• This aggressive approach is generally well-tolerated but requires close monitoring 3
• Electrophysiologic effects begin within 24 hours, though full antiarrhythmic effect takes longer 3

Maintenance Dosing

The goal is to use the lowest effective dose to minimize toxicity:

• Standard maintenance: 200 mg daily for atrial fibrillation 4
• Ventricular arrhythmias: 200-400 mg daily 2, 4
• Doses above 600 mg daily are associated with significantly higher adverse effect rates and should be avoided in long-term therapy 5, 6
• The maintenance dose should be adjusted downward based on clinical response and side effects 7

Critical Dosing Considerations

Delayed Onset of Action

• Amiodarone has an extremely long half-life (approximately 30 days, range 15-100 days) 8
• Full antiarrhythmic effects may not manifest for 90-150 days despite adequate serum levels 2, 8
• Antiarrhythmic protection persists for up to 150 days after discontinuation 8

Dose Adjustments

• Reduce dose by 50-200 mg increments at 3-6 month intervals based on ECG monitoring, plasma levels, and side effects 7
• Most patients require dose reduction from initial maintenance levels due to side effects 5
• In one study, mean doses decreased from 572 mg/day at 45 days to 372 mg/day at 6 months 5

Monitoring Requirements

• Watch for bradycardia, QT prolongation, hypotension, and heart block during loading 2
• Long-term monitoring for pulmonary toxicity, thyroid dysfunction, and hepatic toxicity is essential 2, 4
• Side effects occur in 51-93% of patients on higher maintenance doses 5, 6

Common Pitfalls to Avoid

• Do not use maintenance doses of 600 mg/day routinely - this causes near-universal side effects and forces discontinuation in 10-19% of patients 5, 6
• Do not expect immediate arrhythmia control - the pretherapeutic latency period varies by arrhythmia type and dose 8
• Do not abruptly discontinue - antiarrhythmic effects persist for months due to tissue accumulation 8
• Monitor for drug interactions, particularly with warfarin (increases anticoagulation) and digoxin (increases digoxin levels) 2
• Avoid co-administration with other QT-prolonging medications without expert consultation 2

Intravenous to Oral Transition

When converting from IV to oral amiodarone 2:

• IV duration <1 week: Start 800-1,600 mg oral daily
• IV duration 1-3 weeks: Start 600-800 mg oral daily
• IV duration >3 weeks: Start 400 mg oral daily