What is the recommended dosing regimen for an amiodarone (antiarrhythmic medication) infusion?

Amiodarone Infusion Dosing Regimen

The recommended amiodarone infusion dosing regimen is 150 mg IV over 10 minutes (may be repeated if necessary), followed by 1 mg/min for 6 hours, then 0.5 mg/min for 18 hours, with a total dose not exceeding 2.2 g over 24 hours. 1, 2, 3

Initial Loading Dose

• Administer 150 mg IV over 10 minutes 1, 2, 3
• May repeat the initial bolus if necessary for inadequate response 3
• For life-threatening arrhythmias, this initial bolus is critical to achieve rapid therapeutic levels 2

Maintenance Infusion

• First maintenance phase: 1 mg/min for 6 hours (total of 360 mg) 1, 2, 3
• Second maintenance phase: 0.5 mg/min for 18 hours (total of 540 mg) 1, 2, 3
• Total 24-hour dose should not exceed 2.2 g 1, 2, 3

Administration Considerations

• Use a volumetric infusion pump for accurate delivery 4
• Whenever possible, administer through a central venous catheter dedicated to that purpose 4
• For infusions longer than 1 hour, do not exceed amiodarone concentrations of 2 mg/mL unless using a central venous catheter 4
• Use an in-line filter during administration 4
• For infusions exceeding 2 hours, use glass or polyolefin bottles containing D5W 4

Monitoring Requirements

• Continuous cardiac monitoring is required during administration 2, 3
• Regular blood pressure monitoring is necessary to detect hypotension 2, 3
• Monitor for bradycardia and AV block during infusion 2, 3

Potential Adverse Effects

• Hypotension, especially with rapid administration, is a common adverse effect 2, 3, 4
• Bradycardia and atrioventricular block may occur 2, 3
• Phlebitis, particularly with concentrations >2 mg/mL 3, 4
• Higher doses and faster infusion rates than recommended have resulted in hepatocellular necrosis and acute renal failure 4

Special Considerations

• For breakthrough episodes of ventricular fibrillation or hemodynamically unstable ventricular tachycardia, supplemental infusions of 150 mg amiodarone (mixed in 100 mL of D5W and infused over 10 minutes) may be used 4
• Do not exceed an initial infusion rate of 30 mg/min 4
• Amiodarone has a very long half-life (IV: 9-36 days; Oral: 26-107 days), which affects long-term management strategies 2, 3
• The antiarrhythmic effect begins in less than 30 minutes after administration 3

Cautions

• Use with caution in patients with moderate or severe left ventricular failure due to potential negative inotropic effects 2
• Avoid concomitant use with other QT-prolonging medications when possible 2
• The surface properties of solutions containing injectable amiodarone are altered such that drop counter infusion sets may lead to underdosage by up to 30% 4