What is the dose of Amiodarone (Cordarone)?

Amiodarone (Cordarone) Dosing Guidelines

The recommended amiodarone dosing regimen consists of an oral loading dose of 400-600 mg daily in divided doses for 2-4 weeks, followed by a maintenance dose of 100-200 mg daily for most arrhythmias. 1

Loading Dose Recommendations

• For ventricular arrhythmias: 800-1600 mg per day in divided doses until a total of 10 g has been administered, then transition to maintenance therapy of 200-400 mg per day 1
• For atrial fibrillation: 600-800 mg per day in divided doses until a total of 10 g has been given, then reduce to a maintenance dose of 200 mg per day 1
• Higher initial loading doses (up to 1200 mg daily) may be considered in an inpatient monitoring setting, though this increases the risk of adverse effects 1
• The American Heart Association recommends an oral loading dose of 400-600 mg daily in divided doses for 2-4 weeks for most arrhythmias 1

Maintenance Dose Recommendations

• For most arrhythmias: 100-200 mg daily after loading period 1
• For ventricular arrhythmias: 200-400 mg daily after loading period 1
• For atrial fibrillation: 200 mg daily after loading period 1
• Dose should be reduced if side effects occur, as most adverse effects are dose-dependent 2

Intravenous Dosing

• Initial IV loading: 1000 mg over the first 24 hours 3
• Maintenance IV infusion: 0.5 mg/min (720 mg/24 hours) 3
• For breakthrough VF or unstable VT: 150 mg supplemental infusions over 10 minutes 3
• IV infusion should not exceed 30 mg/min initially 3

Important Dosing Considerations

• Amiodarone shows considerable interindividual variation in response, requiring close monitoring and dose adjustment 3
• The drug has a very long half-life (15-100 days), with a mean of approximately 30 days 4
• Full antiarrhythmic effect may take days to weeks to develop despite adequate serum levels 1
• Therapeutic serum concentrations range between 1.0 and 3.5 μg/ml 5
• Antiarrhythmic protection may persist for up to 150 days after discontinuation 4

Dose Adjustments Based on Response and Toxicity

• Lower maintenance doses should be used whenever possible due to the high frequency of side effects 6
• Reduce dose if side effects occur; most adverse effects are dose-dependent 2
• For pulmonary toxicity (most serious adverse effect), withdraw amiodarone and provide supportive care 2
• If liver enzyme levels are three times higher than normal, discontinue amiodarone unless patient is at high risk for life-threatening arrhythmia 2

Monitoring During Therapy

• Monitor for bradycardia, QT prolongation, hypotension, and heart block during loading phase 1
• Regular monitoring for pulmonary toxicity, thyroid dysfunction, and hepatic toxicity during long-term therapy 1
• Any report from the patient of worsening dyspnea or cough should prompt immediate assessment for pulmonary toxicity 2

Transitioning from IV to Oral Therapy

• For patients receiving IV amiodarone for less than one week: transition to 800-1600 mg oral amiodarone per day 1
• For patients receiving IV amiodarone for 1-3 weeks: transition to 600-800 mg oral amiodarone per day 1
• For patients receiving IV amiodarone for more than 3 weeks: transition to 400 mg oral amiodarone per day 1

Common Pitfalls and Caveats

• Avoid coadministration with other QT-prolonging medications without expert consultation 1
• Be aware of significant drug interactions, particularly with warfarin and digoxin 1
• Amiodarone has numerous serious adverse effects that may limit its usefulness, including pulmonary toxicity (1-17%), thyroid dysfunction, hepatotoxicity, and neurologic effects 7
• The first sign of antiarrhythmic failure may be sudden cardiac death, requiring vigilant monitoring 6