What is the dosing of amiodarone in atrial fibrillation (afib) with rapid ventricular response (RVR)?

From the Guidelines

Amiodarone dosing in atrial fibrillation (AFib) with rapid ventricular response (RVR) is typically initiated with a loading dose of 150 mg over 10 minutes, followed by a maintenance dose of 0.5 to 1 mg/min IV.

Key Considerations

• The loading dose of amiodarone for AFib with RVR is 150 mg over 10 minutes, as recommended by the ACC/AHA/ESC 2006 guidelines 1.
• The maintenance dose is 0.5 to 1 mg/min IV, which can be adjusted based on the patient's response and tolerance to the medication.
• For long-term oral therapy, the dose is typically 200 mg daily, with a loading dose of 800 mg daily for 1 week, followed by 600 mg daily for 1 week, and then 400 mg daily for 4 to 6 weeks 1.
• It's essential to note that amiodarone can be useful for controlling heart rate in patients with AFib when other measures are unsuccessful or contraindicated, as stated in the 2016 ESC guidelines 1.

Clinical Context

• Amiodarone is often used in patients with heart failure or accessory pathway, where other rate control agents may be contraindicated or ineffective 1.
• The choice of amiodarone dosing should be individualized based on the patient's specific clinical context, including the presence of underlying heart disease, renal function, and other comorbidities.
• Close monitoring of the patient's response to amiodarone, including heart rate, blood pressure, and electrocardiogram (ECG) changes, is crucial to ensure safe and effective therapy.

From the FDA Drug Label

Normal subjects over 65 years of age show lower clearances (about 100 mL/h/kg) than younger subjects (about 150 mL/h/kg) and an increase in t½ from about 20 to 47 days. In patients with severe left ventricular dysfunction, the pharmacokinetics of amiodarone are not significantly altered but the terminal disposition t½ of DEA is prolonged Although no dosage adjustment for patients with renal, hepatic, or cardiac abnormalities has been defined during chronic treatment with oral amiodarone, close clinical monitoring is prudent for elderly patients and those with severe left ventricular dysfunction. A placebo-controlled study of IV amiodarone (300 mg over 2 hours followed by 1200 mg/day) in post-coronary artery bypass graft patients with supraventricular and 2- to 3-consecutive-beat ventricular arrhythmias showed a reduction in arrhythmias from 12 hours on

The dosing of amiodarone in atrial fibrillation (afib) with rapid ventricular response (RVR) is not directly stated in the provided drug label. However, based on the information provided for other arrhythmias, IV amiodarone can be administered as a loading dose of 300 mg over 2 hours followed by 1200 mg/day.

• The provided text does not specify the dosing for afib with RVR.
• The studies mentioned in the label are for VT/VF and supraventricular arrhythmias, not specifically for afib with RVR.
• Therefore, the dosing for afib with RVR cannot be directly determined from the provided label 2.

From the Research

Dosing of Amiodarone in Atrial Fibrillation with Rapid Ventricular Response

• The dosing of amiodarone for atrial fibrillation (AF) with rapid ventricular response (RVR) has been studied in various clinical trials 3, 4, 5, 6, 7.
• According to a study published in the American Heart Journal, amiodarone was administered as a 10mg/kg infusion over 30 minutes for the management of recent-onset symptomatic atrial fibrillation 3.
• Another study published in the International Journal of Cardiology reported that intravenous amiodarone has been used as a bolus only or as a bolus followed by a continuous infusion until conversion or up to 24 hours, with a dose range of 3 to 7 mg/kg body weight for the bolus and 900 to 3000 mg/day for the infusion 4.
• A study in the Journal of the American College of Cardiology used an intravenous amiodarone dose of 5 mg/kg body weight in 30 minutes followed by 1,200 mg over 24 hours for the management of recent-onset atrial fibrillation 5.
• In a study published in the Journal of Research in Medical Sciences, intravenous amiodarone (300 mg) was infused for 30 minutes for patients with preexcited atrial fibrillation 6.
• The Journal of Cardiovascular Pharmacology and Therapeutics reported that the most immediate response to intravenous amiodarone is reduction of the ventricular rate, which generally occurs after the first 300-400 mg, and restoration of sinus rhythm may occur after a total dose of 1,000 mg or more 7.

Key Findings

• The efficacy of amiodarone in converting atrial fibrillation to sinus rhythm has been reported to be between 34-69% with bolus only regimens and 55-95% with bolus followed by infusion regimens 4.
• Predictors of successful conversion include shorter duration of atrial fibrillation, smaller left atrial size, and higher amiodarone dose 4.
• Amiodarone is not superior to other antiarrhythmic drugs for pharmacological cardioversion of recent-onset atrial fibrillation but is relatively safe in patients with structural heart disease and depressed left ventricle function 4.