From the Research
For atrial fibrillation, the oral loading dose of amiodarone is typically 400-600 mg three times daily for 1 week, followed by 200 mg three times daily for 1 week, as supported by the most recent study 1. The maintenance dose is usually 200 mg once daily, with some patients requiring a maintenance dose of 100-400 mg daily, adjusted based on individual response and tolerance. Key points to consider when prescribing amiodarone for atrial fibrillation include:
- Amiodarone should be taken with food to reduce gastrointestinal side effects
- Patients should be monitored for potential side effects including thyroid dysfunction, pulmonary toxicity, liver abnormalities, and QT prolongation
- The loading dose is higher initially to achieve therapeutic blood levels quickly, as amiodarone has a very long half-life (approximately 58 days) and takes time to reach steady-state concentrations in the body
- The medication works by blocking potassium channels, which prolongs the cardiac action potential and effective refractory period, helping to maintain normal sinus rhythm in patients with atrial fibrillation, as described in 2 and 3. It's also important to note that amiodarone is a powerful antiarrhythmic medication that can be used in patients with left ventricular dysfunction, congestive heart failure, or hypertrophic cardiomyopathy, as mentioned in 2 and 4. However, the use of amiodarone requires close supervision by the treating physician due to its potential for non-cardiac toxicity and drug-drug interactions, as highlighted in 2 and 3. Overall, the most recent and highest quality study 1 supports the use of a higher loading dose of amiodarone to restore sinus rhythm in patients with postoperative atrial fibrillation, but the standard oral loading dose of 400-600 mg three times daily for 1 week remains a common and effective approach for treating atrial fibrillation.