What are the dosage protocols for IV amiodarone (antiarrhythmic medication) in atrial fibrillation (a fib) in the emergency department (ED) setting?

From the Guidelines

For IV amiodarone in atrial fibrillation in the ED setting, the standard loading dose is 150 mg administered over 10 minutes, followed by a continuous infusion of 1 mg/min for 6 hours, then 0.5 mg/min for the remaining 18 hours, as recommended by the most recent guidelines 1. This dosage protocol is based on the latest evidence from the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia, which provides the most up-to-date and highest quality recommendations for the use of IV amiodarone in atrial fibrillation in the ED setting. Some key points to consider when administering IV amiodarone include:

• The total daily dose should not exceed 2.2 grams 1.
• The medication should be diluted in D5W rather than normal saline to prevent precipitation.
• Continuous cardiac monitoring is essential during administration due to potential adverse effects including hypotension, bradycardia, and QT prolongation 1.
• Amiodarone works by blocking potassium channels, prolonging action potential duration and effective refractory period, which helps restore normal sinus rhythm.
• It's particularly useful in patients with structural heart disease or heart failure where other antiarrhythmics may be contraindicated.
• Blood pressure should be monitored closely during the loading dose, and the infusion rate should be reduced if significant hypotension occurs 1.

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: Initial Load: 150 mg in 100 mL (in D5W) infused over 10 minutes Followed by: 1 mg/min for 6 hours Followed by: 0.5 mg/min thereafter For breakthrough episodes of VF or hemodynamically unstable VT, repeat the Initial Load

The dosage protocol for IV amiodarone in atrial fibrillation (a fib) in the emergency department (ED) setting is as follows:

• Initial Load: 150 mg in 100 mL (in D5W) infused over 10 minutes
• Followed by: 1 mg/min for 6 hours
• Then: 0.5 mg/min thereafter
• Breakthrough episodes: repeat the initial load of 150 mg in 100 mL (in D5W) infused over 10 minutes for VF or hemodynamically unstable VT 2 Key considerations:
• Do not exceed an initial infusion rate of 30 mg/min
• Use a central venous catheter for amiodarone concentrations greater than 2 mg/mL
• Monitor patients closely for hypotension, bradycardia, and AV block, and adjust the dose as needed 2, 2

From the Research

Dosage Protocols for IV Amiodarone in Atrial Fibrillation

The dosage protocols for IV amiodarone in atrial fibrillation (a fib) in the emergency department (ED) setting are as follows:

• A loading dose of 1200 mg intravenous amiodarone in 24 hours has been used in some studies 3
• A bolus dose of 3 to 7 mg/kg body weight, followed by a continuous infusion of 900 to 3000 mg/day, has been reported in other studies 4
• High-dose IV or combined IV and oral administration may be effective as early as 8 hours in patients with recent-onset AF of <48 hour duration in patients without contraindications to these high dose regimens 5
• A dose of 10mg/kg of amiodarone in 30 minutes has been used in some trials 6

Efficacy and Safety of IV Amiodarone

The efficacy and safety of IV amiodarone for pharmacological cardioversion of recent-onset atrial fibrillation have been examined in several studies:

• The efficacy reported is 34-69% with the bolus only regimens, and 55-95% with the bolus followed by infusion regimens 4
• Predictors of successful conversion are shorter duration of atrial fibrillation, smaller left atrial size, and higher amiodarone dose 4
• Amiodarone is not superior to the other antiarrhythmic drugs conventionally used for the pharmacological cardioversion of recent-onset atrial fibrillation but is relatively safe in patients with structural heart disease and in those with depressed left ventricle function 4
• The use of IV amiodarone for acute conversion in patients with an ejection fraction of <40% or clinical heart failure should be limited to symptomatic patients who are refractory to electrical conversion 5

Administration and Monitoring

The administration and monitoring of IV amiodarone in the ED setting should be done with caution:

• The infusion of amiodarone should be associated with a decrease in heart rate and an increase in systolic blood pressure 7
• Beneficial changes have also been noted in pulmonary artery occlusive pressure and cardiac output 7
• Cardiac electrophysiologic consultation should be obtained before using intravenous amiodarone for this purpose 7
• The treatment protocol should include monitoring for adverse effects, such as thrombophlebitis, which has been reported in some studies 3