What is the recommended protocol for Amiodarone (antiarrhythmic medication) infusion?

Amiodarone Infusion Protocol

The recommended protocol for amiodarone infusion is 150 mg administered over 10 minutes as an initial loading dose, followed by 1 mg/min for 6 hours (360 mg), and then 0.5 mg/min for 18 hours (540 mg), with a total dose of approximately 1000 mg over the first 24 hours. 1, 2

Initial Loading and Maintenance Dosing

First 24 Hours

• Loading dose: 150 mg IV over 10 minutes (can be repeated if necessary)
• Early maintenance: 1 mg/min for 6 hours (360 mg)
• Later maintenance: 0.5 mg/min for 18 hours (540 mg)
• Total first 24-hour dose: Approximately 1000 mg

After First 24 Hours

• Maintenance infusion: 0.5 mg/min (720 mg per 24 hours)
• This maintenance infusion can be continued for 2-3 weeks if needed

Administration Guidelines

Infusion Preparation

• Use a concentration of 1-6 mg/mL
• For infusions longer than 1 hour, do not exceed 2 mg/mL unless using a central venous catheter 2
• Administer using a volumetric infusion pump (not drop counter sets, which may lead to underdosing) 2

Administration Route

• Preferably administer through a central venous catheter, especially for concentrations >2 mg/mL 2
• Use an in-line filter during administration 2
• For peripheral administration, use concentrations ≤2.5 mg/mL to minimize phlebitis 2

Solution Compatibility

• Prepare in D5W (5% dextrose in water)
• For infusions exceeding 2 hours, use glass or polyolefin bottles containing D5W 2
• Do not use evacuated glass containers for admixing due to potential precipitation 2

Monitoring During Infusion

Cardiovascular Monitoring

• Continuous ECG monitoring during infusion
• Regular blood pressure monitoring (hypotension occurs in up to 16% of patients) 3
• Monitor for bradycardia and QT prolongation

Breakthrough Arrhythmias

• For breakthrough episodes of ventricular fibrillation or hemodynamically unstable ventricular tachycardia, administer supplemental 150 mg infusions of amiodarone (mixed in 100 mL of D5W and infused over 10 minutes) 2

Important Precautions

Dosing Limitations

• Do not exceed an initial infusion rate of 30 mg/min 2
• Mean daily doses above 2100 mg are associated with increased risk of hypotension 2
• Higher concentrations and faster infusion rates than recommended have resulted in hepatocellular necrosis and acute renal failure 2

Common Adverse Effects

• Hypotension (particularly during loading dose)
• Bradycardia
• Phlebitis (with peripheral administration)
• QT prolongation (rarely torsades de pointes)

Drug Interactions

• Amiodarone increases warfarin effect (reduce warfarin dose by 30-50%) 3
• Doubles serum digoxin levels (reduce digoxin dose) 3
• Increases risk of myopathy/rhabdomyolysis with statins 3
• Potentiates bradycardia with beta-blockers and calcium channel blockers 3

Clinical Pearls

• The hypotensive effect of IV amiodarone may persist throughout the maintenance infusion period, not just during the loading dose 4
• Amiodarone has an extremely long half-life (average 58 days), which impacts long-term management 3
• For patients transitioning to oral therapy, the typical oral loading dose is 600-800 mg daily for several weeks, followed by maintenance of 200-400 mg daily 3, 5
• Infusions of antiarrhythmic drugs should generally be discontinued after 6 to 24 hours, with reassessment of the need for further arrhythmia management 1