Amiodarone for Life-Threatening Arrhythmias: Dosage and Use Recommendations
For life-threatening arrhythmias, amiodarone should be administered as a 150mg IV bolus over 10 minutes, followed by an infusion of 1mg/min for 6 hours, then 0.5mg/min for the next 18 hours, with conversion to oral therapy when possible. 1
IV Administration Protocol
Initial Treatment for Acute Life-Threatening Arrhythmias
- Initial dose: 150mg IV bolus over 10 minutes
- May repeat bolus if needed for breakthrough episodes of VF or hemodynamically unstable VT 2
- First 24 hours: approximately 1000mg total delivered via infusion 2
- Infusion rates:
- First 6 hours: 1mg/min (360mg)
- Next 18 hours: 0.5mg/min (540mg) 1
Important Administration Considerations
- Must be delivered by volumetric infusion pump 2
- Preferably administered through a dedicated central venous catheter 2
- Use an in-line filter during administration 2
- Concentrations >2mg/mL should only be administered via central venous catheter 2
- For infusions >2 hours, concentration should not exceed 2mg/mL unless using central venous access 2
- Infusions >2 hours must be administered in glass or polyolefin bottles containing D5W 2
Oral Therapy Protocol
Standard Loading and Maintenance
- Loading phase: 800-1600mg/day in divided doses until 10g total has been given 1
- Alternative loading: 600-800mg/day in divided doses until 10g total 1
- Maintenance phase: 200-400mg/day 1
Efficacy and Indications
Amiodarone is recommended as first-line therapy for:
- Life-threatening ventricular arrhythmias 1
- Sustained ventricular tachyarrhythmias, especially in patients with left ventricular dysfunction 1
- Atrial fibrillation 1
Amiodarone has demonstrated:
- Superior efficacy compared to other antiarrhythmics 1
- Improved survival and reduced hospital admission rates in shock-resistant, out-of-hospital ventricular fibrillation compared to lidocaine 1
- 65% success rate in maintaining sinus rhythm at 16 months (vs. 37% for sotalol or propafenone) 1
Monitoring Requirements
Due to amiodarone's narrow therapeutic-toxic window, regular monitoring is essential:
- ECG monitoring for QT prolongation 1
- Liver function tests every 6 months 1
- Thyroid function tests every 6 months 1
- Pulmonary function tests 1
- Regular ophthalmologic examinations 1
Important Side Effects and Precautions
Common Adverse Effects
- Pulmonary toxicity (subacute cough, progressive dyspnea, interstitial infiltrates) 1
- Cardiac effects (bradycardia, AV block, QT prolongation) 1
- Thyroid dysfunction 1
- Corneal microdeposits (nearly universal with long-term use) 3
- Gastrointestinal effects, particularly constipation 3
- Neurologic effects (tremor, ataxia) 3
Critical Precautions
- Avoid high concentration/rapid infusion rates which have resulted in hepatocellular necrosis and acute renal failure 2
- Be vigilant about drug interactions, particularly with:
- Use lowest effective dose to minimize toxicity risk 1
- Failure to perform regular surveillance can lead to irreversible damage 1
Special Considerations
- Amiodarone can be used as an adjunct to reduce ICD shock frequency 1
- Not justified for long-term therapy in minimally symptomatic atrial fibrillation patients on anticoagulation 1
- May increase LVEF and decrease worsening heart failure in some patients 1
Common Pitfalls to Avoid
- Using concentrations >3mg/mL in D5W (associated with high incidence of peripheral vein phlebitis) 2
- Using evacuated glass containers for admixing (incompatibility with container buffer may cause precipitation) 2
- Failing to account for amiodarone's adsorption to polyvinyl chloride (PVC) tubing 2
- Inadequate monitoring for toxicity, particularly pulmonary, hepatic, and thyroid effects 1
- Overlooking potential drug interactions, especially with digoxin and warfarin 1, 4