Amiodarone Dosage for Atrial Fibrillation with Rapid Ventricular Response
For atrial fibrillation with rapid ventricular response (AFib RVR), the recommended intravenous amiodarone dosage is 150 mg given over 10 minutes, which may be repeated if necessary, followed by a 1 mg/min infusion for 6 hours, then 0.5 mg/min for 18 hours, with a total 24-hour dose not exceeding 2.2 g. 1
Intravenous (IV) Amiodarone Dosing Protocol
Initial Loading Dose
- 150 mg IV bolus administered over 10 minutes 1
- May be repeated in 10-30 minutes if necessary for inadequate response 1
Maintenance Infusion
- Follow with 1 mg/min infusion for 6 hours (360 mg) 1
- Then reduce to 0.5 mg/min for 18 hours (540 mg) 1
- Total dose over 24 hours should not exceed 2.2 g 1
Administration Considerations
- Use a volumetric infusion pump for accurate delivery 2
- When possible, administer through a central venous catheter dedicated to that purpose 2
- For infusions longer than 1 hour, do not exceed concentrations of 2 mg/mL unless a central venous catheter is used (to avoid phlebitis) 2, 3
- Use an in-line filter during administration 2
Oral Amiodarone for Continued Management
If transitioning to oral therapy after IV administration:
- For patients who received IV amiodarone for less than one week: 800-1,600 mg oral amiodarone daily in divided doses 1
- For patients who received IV amiodarone for 1-3 weeks: 600-800 mg oral amiodarone daily 1
- For patients who received IV amiodarone for more than 3 weeks: 400 mg oral amiodarone daily 1
- Long-term maintenance: 200 mg daily after a loading period (typically after a total of 10 g has been given) 1
Efficacy and Onset of Action
- Antiarrhythmic effect begins in less than 30 minutes 1
- Slows ventricular response in nearly all patients with AFib RVR 4
- Conversion to sinus rhythm occurs in approximately 46-50% of patients within the first 30 minutes 1, 4
- Additional conversions may occur within 2-8 hours after administration 4
Monitoring Requirements
- Continuous ECG monitoring during administration 1
- Regular blood pressure monitoring to detect hypotension 1
- Monitor for bradycardia and AV block 1
Potential Adverse Effects
- Hypotension (especially with rapid administration) 1
- Bradycardia 1
- Atrioventricular block 1
- Phlebitis (particularly with concentrations >2 mg/mL) 1, 2
- QT prolongation (with longer-term use) 1
Special Considerations
- Higher doses (>1500 mg/day) show better efficacy for conversion to sinus rhythm 5
- Amiodarone may be particularly beneficial in patients with structural heart disease or impaired left ventricular function where other antiarrhythmics are contraindicated 5
- For long-term therapy, use the lowest effective dose to minimize toxicity risk 1
- Amiodarone has a very long half-life (IV: 9-36 days; Oral: 26-107 days), which affects dosing strategies for long-term management 1
Remember that while amiodarone is effective for rate control in AFib RVR, its long-term use carries significant toxicity risks affecting multiple organ systems, including pulmonary, thyroid, hepatic, ocular, and neurological complications 1, 6.