What is the typical dose of Amiodarone for treating arrhythmias?

Amiodarone Dosing Guidelines for Arrhythmias

The typical dosing of amiodarone for treating arrhythmias involves 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, as recommended by the American Heart Association. 1

Dosing Based on Arrhythmia Type

Ventricular Arrhythmias

• For ventricular arrhythmias, start with 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, 2
• For hemodynamically stable monomorphic ventricular tachycardia requiring IV therapy, administer 150 mg over 10 minutes (repeatable if necessary), followed by 1 mg/min infusion for 6 hours, then 0.5 mg/min, with total 24-hour dose not exceeding 2.2 g 2

Atrial Fibrillation

• For atrial fibrillation, use 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
• Lower maintenance doses (100-400 mg/day) are often sufficient for controlling recurrent supraventricular tachycardia or atrial fibrillation 3

Loading Dose Considerations

• 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 loading phase is necessary because amiodarone has a very long half-life (approximately 30 days), and the full antiarrhythmic effect may take days to weeks to develop 1, 3
• Some clinical studies have used more aggressive loading protocols (50 mg/kg per day for 3 days, then 30 mg/kg per day for 2 days) in patients with life-threatening arrhythmias, but these require careful monitoring 4

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, 2
• For patients receiving IV amiodarone for 1-3 weeks, transition to 600-800 mg oral amiodarone per day 1, 2
• For patients receiving IV amiodarone for more than 3 weeks, transition to 400 mg oral amiodarone per day 1, 2

Monitoring and Adverse Effects

• Essential monitoring during loading: watch for bradycardia, QT prolongation, hypotension, and heart block 1
• Side effects are dose-dependent and extremely common (occurring in up to 93% of patients in some studies) 5
• The most serious potential adverse effect is pulmonary toxicity, presenting as subacute cough and progressive dyspnea 2
• Monitor for thyroid dysfunction and hepatic toxicity during long-term therapy 1
• Frequency of adverse effects correlates with total amiodarone exposure (dosage and duration), so use the lowest effective dose possible 2

Important Clinical Considerations

• Avoid coadministration with other QT-prolonging medications without expert consultation 1
• Be aware of significant drug interactions, particularly with warfarin and digoxin 1
• In patients with structural heart disease and life-threatening ventricular arrhythmias, consider implantable cardioverter-defibrillators as primary therapy, with amiodarone as an adjunct 2
• The dose may need to be reduced if side effects occur - in clinical practice, maintenance doses are often lowered from initial targets due to adverse effects 5, 6