What is the proper infusion protocol for amiodarone with D5 water (dextrose 5% water) in an adult patient with life-threatening arrhythmias?

How to Infuse Amiodarone with D5 Water

Amiodarone must be diluted in D5W (dextrose 5% in water) and administered through a central venous catheter whenever possible using a volumetric infusion pump with an in-line filter. 1

Preparation and Equipment Requirements

• Always use D5W as the diluent - amiodarone is incompatible with normal saline and forms precipitates with multiple other medications 1
• Use a volumetric infusion pump - drop counter infusion sets can underdose patients by up to 30% due to altered surface properties of amiodarone solutions 1
• Insert an in-line filter during administration 1
• Administer through a central venous catheter for concentrations >2 mg/mL, as peripheral vein phlebitis occurs frequently at higher concentrations 2, 1
• Use glass or polyolefin bottles (not evacuated glass containers which may cause precipitation) for infusions exceeding 2 hours 1

Standard Dosing Protocol for Life-Threatening Arrhythmias

First 24 Hours (Loading Phase)

For hemodynamically stable patients:

• Loading dose: 150 mg (5 mg/kg or approximately 300 mg) over 1 hour 3
• Followed by maintenance infusion: 1 mg/min for 6 hours (360 mg) 2
• Then reduce to: 0.5 mg/min for the remaining 18 hours (540 mg) 2, 1
• Total first 24-hour dose: approximately 1000 mg 1

For cardiac arrest or immediately life-threatening situations:

• Rapid loading: 150 mg over 10-15 minutes 3, 2
• Can repeat after 1 hour if needed 3

Breakthrough Arrhythmias

• Supplemental bolus: 150 mg in 100 mL D5W over 10 minutes to minimize hypotension risk 1
• Do not exceed initial infusion rate of 30 mg/min 1

Maintenance Phase (After 24 Hours)

• Continue at 0.5 mg/min (720 mg per 24 hours) 1
• Can be continued for 2-3 weeks regardless of age, renal function, or left ventricular function 1
• Infusion rate may be increased to achieve effective arrhythmia suppression, but mean daily doses >2100 mg are associated with increased hypotension risk 1

Concentration Guidelines

• For infusions >1 hour: do not exceed 2 mg/mL concentration unless using a central venous catheter 1
• Concentrations >3 mg/mL in D5W are associated with high incidence of peripheral vein phlebitis 1
• Acceptable concentration range: 1-6 mg/mL when using central venous access 1

Critical Safety Monitoring

Cardiovascular Monitoring

• Continuous ECG monitoring is mandatory for heart rate, AV conduction abnormalities, and QT prolongation 2
• Hypotension occurs in 16-26% of patients during IV administration 2, 4
• Bradycardia occurs in 4.9% of patients regardless of dose 2
• If bradycardia or heart block develops: discontinue infusion or reduce rate immediately 2

Absolute Contraindications

• Second- or third-degree heart block without pacemaker 2
• Severe bradycardia without pacemaker support 2

Special Precautions in Bradycardic Patients

• Use extreme caution if heart rate <60 bpm - relatively contraindicated unless pacemaker in place or immediately life-threatening situation with no safer alternatives 2
• Monitor for heart rate decrease of ≥10 bpm during infusion - if occurs, reduce infusion rate 2

Drug Interactions Requiring Dose Adjustments

• Reduce digoxin dose by 50% when starting amiodarone, as digoxin levels predictably double 2
• Reduce warfarin dose by one-third to one-half and monitor INR at least weekly for first 6 weeks 2
• Avoid concomitant beta-blockers, calcium channel blockers, or digoxin when possible, as they create additive bradycardia effects 2

Important Administration Warnings

• Intravenous amiodarone at much higher concentrations and faster rates than recommended has resulted in hepatocellular necrosis and acute renal failure leading to death 1
• Anaphylactic shock, though rare, can occur - be prepared with physiologic saline, dopamine, and methylprednisolone 5
• Do not use plastic containers in series connections due to air embolism risk 1

Transition to Oral Therapy

When switching from IV to oral amiodarone after varying durations:

• After <1 week IV: 800-1600 mg PO daily 1
• After 1-3 weeks IV: 600-800 mg PO daily 1
• After >3 weeks IV: 400 mg PO daily 1
• These recommendations assume 50% bioavailability of oral amiodarone and a 720 mg/day IV infusion rate 1