What is the recommended dosing regimen for Amiodarone (antiarrhythmic medication) drip in an adult patient with life-threatening arrhythmias?

Amiodarone Drip Dosing for Life-Threatening Arrhythmias

For adult patients with life-threatening ventricular arrhythmias, administer amiodarone as a 150 mg IV bolus over 10 minutes, followed by 1 mg/min infusion 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

First 24 Hours:

• Loading bolus: 150 mg IV over 10 minutes (can be repeated if VT recurs) 1, 3
• First 6 hours: 1 mg/min continuous infusion (360 mg total) 1, 2, 3
• Remaining 18 hours: 0.5 mg/min continuous infusion (540 mg total) 1, 2, 3
• Total first 24 hours: Approximately 1000 mg 3

For cardiac arrest with VF/pulseless VT unresponsive to defibrillation: Use 300 mg IV/IO bolus, with a second 150 mg bolus if the rhythm persists 2

Maintenance Infusion Beyond 24 Hours

• Continue at 0.5 mg/min (720 mg per 24 hours) for up to 2-3 weeks 3
• The infusion rate may be increased to achieve effective arrhythmia suppression 3
• Mean daily doses above 2100 mg are associated with increased risk of hypotension 3

Breakthrough Arrhythmias

If VF or hemodynamically unstable VT recurs during maintenance infusion:

• Administer supplemental 150 mg bolus mixed in 100 mL D5W over 10 minutes 3
• This minimizes potential for hypotension 3

Critical Administration Requirements

Concentration and venous access:

• For concentrations >2 mg/mL: Central venous catheter is mandatory 2, 3
• For infusions >1 hour: Do not exceed 2 mg/mL concentration unless using a central line 2, 3
• Concentrations >3 mg/mL are associated with high incidence of peripheral vein phlebitis 3

Equipment requirements:

• Must use volumetric infusion pump (drop counter sets can underdose by up to 30%) 3
• Use in-line filter during administration 3
• Administer in glass or polyolefin bottles containing D5W for infusions exceeding 2 hours 3
• Do not use evacuated glass containers for admixing 3

Monitoring Parameters

Cardiovascular monitoring:

• Hypotension occurs in 16% of IV patients 2
• Bradycardia occurs in 4.9% of IV patients 2
• Monitor for AV block, heart block, and QT prolongation 1, 2
• Continuous cardiac monitoring is essential 2

Common pitfall: Do not exceed initial infusion rate of 30 mg/min, as faster rates have resulted in hepatocellular necrosis and acute renal failure leading to death 3

Contraindications

Absolute contraindications without pacemaker availability:

• Second- or third-degree AV block 2
• Sick sinus syndrome 2
• Severe sinus node dysfunction 2

Transition to Oral Therapy

When converting from IV to oral amiodarone:

• <1 week of IV: 800-1600 mg oral daily 1, 4
• 1-3 weeks of IV: 600-800 mg oral daily 1, 4
• >3 weeks of IV: 400 mg oral daily 1
• Continue oral loading until total of 10 g administered, then reduce to maintenance dose of 200-400 mg daily 1, 4

Drug interaction adjustments during transition:

• Reduce digoxin dose by 50% immediately (amiodarone doubles digoxin levels) 4
• Reduce warfarin dose by 30-50% and check INR within 3-5 days 4