From the Guidelines
Amiodarone for atrial fibrillation should be initiated with a low-dose regimen of 200 mg daily or less, as it is effective and associated with fewer side effects compared to higher-dose regimens. The use of amiodarone is recommended for the long-term maintenance of sinus rhythm in patients with paroxysmal or persistent atrial fibrillation (AF) refractory to other drugs 1. The duration of treatment varies based on individual patient factors, but it is often long-term or lifelong for persistent atrial fibrillation.
Key Considerations
- Amiodarone is more effective than class I drugs, sotalol, or placebo in maintaining sinus rhythm, but it is associated with a relatively high incidence of potentially severe extracardiac toxic effects 1.
- The drug increases the success rate of electric cardioversion and prevents relapses by suppressing atrial ectopy in patients with persistent AF 1.
- Important considerations include monitoring for side effects such as thyroid dysfunction, pulmonary toxicity, and liver abnormalities, which requires baseline and periodic testing of thyroid function, liver enzymes, pulmonary function, and eye examinations.
- Amiodarone has numerous drug interactions due to its effects on cytochrome P450 enzymes, so medication reconciliation is essential.
Treatment Regimen
- A loading dose is not always necessary, but if used, it should be individualized based on patient factors.
- The maintenance dose of 200 mg daily or less is recommended for long-term treatment.
- For acute conversion of atrial fibrillation, intravenous administration may be used, but this should be done under close monitoring due to the risk of side effects.
Patient Selection
- Amiodarone is an appropriate initial choice for patients with left ventricular hypertrophy (LVH), heart failure (HF), coronary artery disease (CAD), and/or previous myocardial infarction (MI), as it is associated with a low risk of proarrhythmia 1.
- Patients with paroxysmal or persistent AF who are refractory to other drugs may also benefit from amiodarone treatment.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Recommended Dose of Amiodarone
- The recommended dose of Amiodarone for atrial fibrillation varies, but maintenance dosages of 200 to 400 mg/day have been used in some studies 2, 3.
- In other studies, higher doses have been used, such as 600 mg/day for one week, followed by 400 mg/day for three weeks 4, 5.
- Intravenous doses of 300 mg over 1 hour, followed by 20 mg/kg over 24 hours, have also been used 4, 5.
Duration of Amiodarone Treatment
- The duration of Amiodarone treatment for atrial fibrillation can vary, but treatment for several weeks or months is common 2, 3, 4, 5.
- In some studies, treatment was continued until conversion to sinus rhythm or for a maximum of 3-4 weeks 6, 4, 5.
- The duration of treatment may be influenced by factors such as the size of the left atrium and the duration of atrial fibrillation, with longer treatment durations required for patients with larger left atria or longer durations of atrial fibrillation 6, 4, 5.
Factors Influencing Treatment Outcome
- The size of the left atrium and the duration of atrial fibrillation can influence the outcome of Amiodarone treatment, with larger left atria and longer durations of atrial fibrillation decreasing the effectiveness of treatment 2, 6, 4, 5.
- The dose of Amiodarone used can also influence the outcome of treatment, with higher doses being more effective in some studies 6, 4, 5.