What is the dose of Amiodarone (amiodarone) for new-onset atrial fibrillation (AFib)?

From the Guidelines

For new onset atrial fibrillation, the recommended dose of amiodarone is a loading dose of 600 to 800 mg per day in divided doses until a total of 10 g has been given, followed by a maintenance dose of 200 mg per day. This dosing regimen is based on the guidelines for the management of patients with atrial fibrillation, as outlined in the study by 1. The study suggests that amiodarone is effective in maintaining sinus rhythm and preventing recurrence of atrial fibrillation, with a success rate of 69% compared to 39% with propafenone or sotalol over a 16-month follow-up period. However, it's essential to closely monitor patients for potential side effects, including hypotension, bradycardia, QT prolongation, and extracardiac toxic effects such as thyroid dysfunction, pulmonary toxicity, liver abnormalities, and corneal deposits.

Some key points to consider when administering amiodarone for new onset atrial fibrillation include:

• The use of a loading dose to rapidly achieve therapeutic levels of the drug
• The importance of close monitoring for potential side effects, including ECG monitoring, blood pressure checks, and observation for signs of toxicity
• The need to adjust the dose based on the patient's response to treatment and the presence of any side effects
• The potential for amiodarone to interact with other medications, including warfarin, digoxin, and beta blockers

It's also worth noting that amiodarone is typically reserved for patients who have not responded to other antiarrhythmics or have structural heart disease where other agents may be contraindicated, due to its potential for serious side effects. However, in patients with ischemic heart disease, sotalol may be preferred due to its lower toxicity profile, as suggested by the study by 2. Overall, the use of amiodarone for new onset atrial fibrillation requires careful consideration of the potential benefits and risks, as well as close monitoring and adjustment of the dose as needed.

From the FDA Drug Label

The recommended starting dose of amiodarone is about 1000 mg over the first 24 hours of therapy, delivered by the following infusion regimen: The first 24-hour dose may be individualized for each patient; however, in controlled clinical trials, mean daily doses above 2100 mg were associated with an increased risk of hypotension.

The dose of amiodarone for new onset AFib is 1000 mg over the first 24 hours of therapy. The dose may be individualized, but daily doses above 2100 mg are associated with an increased risk of hypotension 3.

From the Research

Dose of Amiodarone for New Onset AFib

• The dose of amiodarone for new onset atrial fibrillation (AFib) varies depending on the study and the patient population.
• A study published in 2008 4 used a loading dose of 300 mg followed by a continuous infusion of 1200 mg/24 h in critically ill patients with new-onset AFib.
• Another study published in 2012 5 used a single high oral dose of 30 mg/kg amiodarone for cardioversion of recent onset AFib.
• A study published in 2000 6 used a single oral dose of 30 mg/kg amiodarone for recent-onset AFib and found it to be effective and safe.
• A meta-analysis published in 2021 7 compared the efficacy of single-dose oral anti-arrhythmic drugs, including amiodarone, for cardioversion of recent-onset AFib and found that amiodarone was not superior to other agents such as flecainide and propafenone at 8 hours, but was effective at longer follow-up.

Comparison of Amiodarone Doses

• The dose of amiodarone used in the studies ranged from 200 to 400 mg/d 8 for maintenance of normal sinus rhythm in patients with resistant chronic AFib.
• A single oral dose of 30 mg/kg amiodarone was used in several studies 5, 6 for cardioversion of recent-onset AFib.
• The choice of amiodarone dose may depend on the patient population, the severity of the AFib, and the presence of other medical conditions.

Efficacy and Safety of Amiodarone

• Amiodarone has been shown to be effective in converting AFib to sinus rhythm in several studies 4, 5, 6.
• The drug has also been shown to be safe and well-tolerated in most patients, although it can cause gastrointestinal symptoms and other adverse effects 5, 6.
• A meta-analysis published in 2021 7 found that amiodarone was associated with a low risk of atrial and ventricular tachyarrhythmias, bradyarrhythmias, and hypotension.