Amiodarone Infusion Dosing
For life-threatening ventricular arrhythmias (VF/pVT), administer a 150 mg IV bolus over 10 minutes, followed by 1 mg/min for 6 hours, then 0.5 mg/min for the remaining 18 hours of the first 24 hours. 1
Standard Dosing Regimen (First 24 Hours)
The FDA-approved dosing delivers approximately 1000 mg over the first 24 hours using this three-phase approach 1:
- Loading bolus: 150 mg IV over 10 minutes (can repeat once in 10-30 minutes if needed for breakthrough VF/pVT)
- Fast infusion: 1 mg/min for 6 hours (360 mg total)
- Maintenance infusion: 0.5 mg/min for 18 hours (540 mg total)
This regimen is supported by the 2018 AHA ACLS guidelines, which recommend amiodarone (300 mg initial dose, 150 mg second dose) for shock-refractory VF/pVT 2. The FDA label specifies 150 mg boluses for practical administration 1.
Maintenance Infusion (After 24 Hours)
Continue 0.5 mg/min (720 mg per 24 hours) for up to 2-3 weeks, using concentrations of 1-6 mg/mL 1. The infusion rate may be increased to achieve effective arrhythmia suppression, though mean daily doses above 2100 mg increase hypotension risk 1.
Critical Administration Details
Concentration and Access
- Use concentrations ≤2 mg/mL for peripheral IV to minimize phlebitis risk 1
- Concentrations >2 mg/mL require central venous catheter 1
- Always use a volumetric infusion pump (not drop counters, which can underdose by 30%) 1
- Use an in-line filter during administration 1
Preparation
- Mix in D5W only (not normal saline) 1
- Use glass or polyolefin bottles for infusions >1 hour 1
- Do not use evacuated glass containers (causes precipitation) 1
Context-Specific Considerations
Cardiac Arrest (VF/pVT)
For shock-refractory VF/pVT, the 2018 AHA guidelines support 300 mg IV/IO initially, then 150 mg if needed 2. This recommendation is based on improved survival to hospital admission in witnessed arrests, though long-term survival benefit remains unproven 2. The polysorbate-based formulation (not captisol-based premixed) is needed for rapid bolus administration during arrest 2.
Atrial Fibrillation
For acute atrial fibrillation, use the same loading regimen (150 mg over 10 minutes, then 1 mg/min for 6 hours, then 0.5 mg/min) 3, 1. However, long-term amiodarone for rate control alone is not justified in relatively asymptomatic patients on anticoagulation, given toxicity risks 3.
Major Pitfalls and Monitoring
Hypotension Risk
Hypotension is the most common acute adverse effect and persists throughout the maintenance infusion, not just during loading 4. This is caused by the polysorbate 80 and benzyl alcohol cosolvents, not the amiodarone itself 4, 5. Management:
- Never exceed 30 mg/min initial infusion rate 1
- Slow or temporarily stop infusion if hypotension develops
- Consider reducing catecholamine requirements as amiodarone takes effect 6
Other Acute Risks
- Bradycardia and AV block (especially in pediatrics: 20% and 15% respectively) 1
- Hepatocellular necrosis and acute renal failure with excessively high concentrations or rapid rates 1
- QT prolongation (though rarely causes torsades de pointes) 3
Pediatric Dosing
In children, use 5 mg/kg bolus over 60 minutes, followed by 10-20 mg/kg/day continuous infusion 6, 7. This achieves effective serum concentrations (1.30-2.06 µM/L) with 90% arrhythmia suppression 8. Avoid in neonates <1 month due to benzyl alcohol-related "gasping syndrome" risk 1.
Transition to Oral Therapy
When converting from IV to oral 3:
- <1 week IV: 800-1600 mg/day oral
- 1-3 weeks IV: 600-800 mg/day oral
- >3 weeks IV: 400 mg/day oral
Load oral therapy until 10 g total dose achieved, then reduce to 200-400 mg/day maintenance 3.