What is the recommended administration protocol for an amiodarone (antiarrhythmic medication) drip in a patient with life-threatening ventricular arrhythmias?

Amiodarone Infusion Protocol for Life-Threatening Ventricular Arrhythmias

For life-threatening ventricular arrhythmias (VF or hemodynamically unstable VT), administer amiodarone as 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, with a maximum total dose of 2.2 g over 24 hours. 1, 2

Initial Loading Protocol

The three-stage infusion protocol delivers approximately 1000 mg over the first 24 hours 2:

• Rapid loading: 150 mg IV over 10 minutes (can mix in 100 mL D5W) 1, 2
• Early maintenance: 1 mg/min for 6 hours (360 mg total) 1, 2
• Late maintenance: 0.5 mg/min for 18 hours (540 mg total) 1, 2

Cardiac Arrest Dosing

For VF/pulseless VT unresponsive to defibrillation and epinephrine 1:

• First dose: 300 mg IV/IO bolus over 10 minutes 1
• Second dose: 150 mg IV/IO bolus if rhythm persists 1

Breakthrough Arrhythmias

• Administer 150 mg supplemental infusions (mixed in 100 mL D5W over 10 minutes) for breakthrough VF or hemodynamically unstable VT episodes 2
• Do not exceed an initial infusion rate of 30 mg/min 2

Administration Requirements

Central line access is mandatory for concentrations >2 mg/mL 1, 2:

• For infusions >1 hour, do not exceed 2 mg/mL concentration unless using a central line 1
• Concentrations >3 mg/mL are associated with high incidence of peripheral vein phlebitis 2
• Use a volumetric infusion pump (not drop counters, which can underdose by up to 30%) 2
• Use an in-line filter during administration 2

Solution Preparation

• Administer in glass or polyolefin bottles containing D5W for infusions exceeding 2 hours 2
• Do not use evacuated glass containers for admixing (may cause precipitation) 2
• Amiodarone adsorbs to PVC tubing and leaches plasticizers including DEHP, especially at higher concentrations and lower flow rates 2

Monitoring Requirements

Close monitoring is essential due to dose-related adverse effects 1:

• Hypotension: Occurs in 16% of IV patients—monitor blood pressure continuously during loading 1
• Bradycardia: Occurs in 4.9% of IV patients—monitor heart rate continuously 1
• AV block and heart block: Check ECG regularly 1
• QT prolongation: Monitor ECG for excessive prolongation 1
• Phlebitis: Inspect infusion site frequently 1

Maintenance Infusion

• Continue 0.5 mg/min (720 mg per 24 hours) after the first 24 hours 2
• May increase maintenance infusion rate to achieve effective arrhythmia suppression 2
• Can continue for 2-3 weeks regardless of age, renal function, or left ventricular function 2
• Mean daily doses above 2100 mg are associated with increased risk of hypotension 2

Critical Safety Warnings

Intravenous amiodarone loading at concentrations and rates much higher than recommended have resulted in hepatocellular necrosis and acute renal failure leading to death 2:

• Strictly adhere to recommended concentrations and infusion rates 2
• Use central venous catheter whenever possible 2

Contraindications

Do not administer without a pacemaker in patients with 1:

• Second- or third-degree AV block 1
• Sick sinus syndrome 1
• Severe sinus node dysfunction 1
• Heart transplant recipients 1

Efficacy Data

Amiodarone demonstrates dose-response efficacy in refractory ventricular arrhythmias 3:

• Higher doses (500-1000 mg/24h) show significantly longer time to first arrhythmic event compared to lower doses (125 mg/24h) 3
• Median event rates decrease from 0.07 to 0.02 events per hour with increasing doses 3
• 78% of patients survived to at least 48 hours in dose-ranging studies 3
• Equally effective as bretylium but better tolerated with less hypotension 4