How to administer a Cordarone (Amiodarone) drip?

How to Administer Cordarone (Amiodarone) Drip

For life-threatening ventricular arrhythmias, 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 (total ~1,050 mg over 24 hours). 1, 2, 3

Initial Loading Protocol

Rapid Bolus Dose

• Give 150 mg IV diluted in 100 mL D5W over 10 minutes for sustained monomorphic VT without severe hemodynamic compromise 1, 2, 3
• For cardiac arrest with VF/pulseless VT unresponsive to defibrillation and epinephrine, use 300 mg IV/IO bolus, with a second 150 mg bolus if rhythm persists 2
• Do not exceed an initial infusion rate of 30 mg/min 3

Maintenance Infusion Phases

First 6 hours: 1 mg/min (360 mg total) 1, 2, 3

Next 18 hours: 0.5 mg/min (540 mg total) 1, 2, 3

After 24 hours: Continue 0.5 mg/min (720 mg per 24 hours) for up to 2-3 weeks 3

Supplemental Dosing

• For breakthrough VF or hemodynamically unstable VT, give 150 mg supplemental infusions (mixed in 100 mL D5W over 10 minutes) 3
• The maintenance infusion rate may be increased to achieve effective arrhythmia suppression, but mean daily doses above 2,100 mg are associated with increased risk of hypotension 3

Critical Administration Requirements

Vascular Access and Concentration

• Use a central venous catheter whenever possible 2, 3
• For concentrations >2 mg/mL, a central line is mandatory 2, 3
• For infusions >1 hour, do not exceed 2 mg/mL concentration unless using a central line, as peripheral vein phlebitis occurs frequently with higher concentrations 2, 3
• Use an in-line filter during administration 3

Equipment and Solutions

• Must use a volumetric infusion pump (not drop counters, which can underdose by up to 30%) 3
• Administer in glass or polyolefin bottles containing D5W for infusions exceeding 2 hours 3
• Do not use evacuated glass containers for admixing (may cause precipitation) 3
• PVC tubing is acceptable (all clinical experience used PVC), though it leaches plasticizers including DEHP 3

Mandatory Monitoring During Infusion

Continuous ECG Monitoring

Monitor for the following dose-related adverse effects throughout the infusion 2, 4:

• Hypotension (occurs in 16% of IV patients) 2, 4
• Bradycardia (occurs in 4.9% of IV patients) 2, 4
• AV block and heart block 2, 4
• QT prolongation 2, 4

Vital Sign Parameters

• Stop or slow infusion if:
  • Systolic blood pressure falls below 100 mm Hg 1
  • Heart rate drops below 50 bpm 1
• Monitor for phlebitis at infusion site 2

Absolute Contraindications

Do not administer amiodarone without a functioning pacemaker in patients with: 2, 4

• Second- or third-degree AV block 2, 4
• Sick sinus syndrome 2
• Severe sinus node dysfunction 2

Additional contraindications: 2

• Acute inflammatory lung disease 2
• Patients who have had a heart transplant 2

Critical Drug Interactions

Before Starting Infusion

Assess for concomitant medications that increase bradycardia risk 4:

• Beta-blockers (create additive AV nodal suppression) 4
• Calcium channel blockers (substantially increase risk of heart block during bolus) 4
• Digoxin (reduce dose by 50% when starting amiodarone, as levels will double) 2, 4

During and After Infusion

• Warfarin: Reduce dose by 33-50% and monitor INR at least weekly (interaction peaks at 7 weeks) 2
• Avoid concomitant QT-prolonging drugs without expert consultation 2, 5

Special Populations

Hepatic Dysfunction

• Use with extreme caution in hepatic dysfunction 2
• Intravenous amiodarone loading infusions at much higher concentrations and rates than recommended have resulted in hepatocellular necrosis and acute renal failure, leading to death 3

Heart Failure

• The standard bolus protocol remains appropriate for acute life-threatening arrhythmias in patients with severe heart failure 4
• Amiodarone does not typically produce clinically significant cardiodepression in patients with left ventricular dysfunction 4

Elderly Patients

• Dosing varies considerably depending on age, weight, and hepatic and renal function 1
• Clinical monitoring is particularly important when changing to oral therapy 3

Transitioning to Oral Amiodarone

When switching from IV to oral amiodarone, the dose depends on duration of IV therapy 5, 3:

IV <1 week: Start 800-1,600 mg oral daily 5, 3

IV 1-3 weeks: Start 600-800 mg oral daily 5, 3

IV >3 weeks: Start 400 mg oral daily 5, 3

These recommendations account for the 50% bioavailability of oral amiodarone and the significant tissue stores already accumulated during IV therapy 5, 3

Common Pitfalls to Avoid

• Never use drop counter infusion sets (causes up to 30% underdosing) 3
• Never infuse concentrations >2 mg/mL peripherally for >1 hour (severe phlebitis risk) 2, 3
• Never administer faster than 30 mg/min initially (risk of hepatocellular necrosis) 3
• Never give to patients with high-degree AV block without a pacemaker (can cause complete heart block) 2, 4
• Do not drink grapefruit juice during oral amiodarone therapy (inhibits CYP3A metabolism) 3

Duration of Therapy

• Infusions may be used after an episode of VT/VF but should be discontinued after 6-24 hours and the need for further arrhythmia management assessed 1
• A maintenance infusion of up to 0.5 mg/min can be continued for 2-3 weeks regardless of age, renal function, or left ventricular function 3
• There has been limited experience with IV amiodarone for longer than 3 weeks 3