How to Convert from Multaq (Dronedarone) to Amiodarone
Stop dronedarone immediately and begin amiodarone loading without any washout period, as dronedarone has a short half-life (~24 hours) and does not require a waiting period before initiating amiodarone. 1
Conversion Protocol
Step 1: Discontinue Dronedarone
- Stop dronedarone immediately - no tapering required
- Dronedarone's half-life is approximately 24 hours, resulting in minimal tissue accumulation 2
- The FDA label explicitly states that Class III antiarrhythmics (including amiodarone) must be stopped before starting dronedarone, but the reverse conversion does not require a washout period 1
Step 2: Initiate Amiodarone Loading
Oral Loading Regimen (Preferred for Stable Patients):
- 600-800 mg daily in divided doses until 10-12 g total load is achieved 2
- Then maintenance: 200 mg daily 2
- Can be done as outpatient if patient is stable and in sinus rhythm 3
Intravenous Loading (for Unstable Patients or Urgent Situations):
- 150 mg IV bolus over 10 minutes
- Then 1 mg/min for 6 hours
- Then 0.5 mg/min for 18 hours
- Transition to oral dosing when appropriate 3, 4
Step 3: Monitoring During Conversion
Immediate Monitoring (First 48-72 Hours):
- ECG monitoring for QT interval prolongation and bradycardia 2
- Baseline ECG before starting amiodarone 2
- Monitor for heart rate <50 bpm or high-degree AV block 2
Ongoing Surveillance:
- Liver function tests and thyroid function tests every 6 months 2
- Annual chest radiograph for pulmonary toxicity 2
- Baseline pulmonary function tests if available 2
Key Clinical Considerations
Why No Washout is Needed
Unlike converting FROM amiodarone (which has a 20-100 day half-life requiring weeks of washout), dronedarone's 24-hour half-life means it clears rapidly 2. Research evidence supports immediate switching is safe and well-tolerated 5, 6.
Drug Interaction Management
Adjust doses of these medications when starting amiodarone:
- Digoxin: Reduce dose by 50% (amiodarone inhibits P-glycoprotein) 2
- Warfarin: Reduce dose and monitor INR closely (expect 0-200% increase) 3
- Statins: Use lower doses to avoid myopathy risk 2
Contraindications to Amiodarone (Screen Before Converting)
Do NOT convert to amiodarone if patient has:
- Active hepatitis or significant chronic liver disease 2
- Pulmonary interstitial abnormalities 2
- Preexisting QTc >500 ms 2
- Iodine hypersensitivity 2
- High-degree AV block without pacemaker 2
Common Pitfalls to Avoid
Do NOT:
- Wait for dronedarone washout - this unnecessarily leaves patient without antiarrhythmic coverage
- Use both drugs simultaneously - this is contraindicated 1
- Forget to counsel about photosensitivity with amiodarone (use sun protection diligently) 2
- Miss baseline thyroid/liver function tests before starting amiodarone 2
Do:
- Verify patient is in sinus rhythm or can be cardioverted (amiodarone should not be first-line if other options exist) 2
- Ensure appropriate anticoagulation continues throughout conversion 7, 8
- Educate patient about symptoms of pulmonary toxicity (persistent nonproductive cough, dyspnea) 2, 4
- Document reason for conversion (typically dronedarone failure or contraindication developed) 2
Special Populations
Heart Failure Patients:
- Amiodarone is appropriate for NYHA Class I-II stable heart failure 2, 9
- Dronedarone is contraindicated in NYHA Class III-IV or recent decompensation, making amiodarone the only option 2, 1
Permanent Atrial Fibrillation:
- Neither drug should be used in permanent AF 10, 1
- If patient has converted to permanent AF while on dronedarone, consider rate control strategy instead 10
Evidence Quality Note
The conversion protocol is based on pharmacokinetic principles from FDA labeling 1 and guideline recommendations 2. Direct research evidence from the ARTEMIS AF studies supports immediate switching is safe when converting FROM amiodarone TO dronedarone 5, and the reverse conversion (dronedarone to amiodarone) is even more straightforward given dronedarone's shorter half-life 6.