====== Dronedarone (Multaq®) ======

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<WRAP infobox>
^ Dronedarone | {{ :cardio:arrhythmias:dronedarone_structure.svg?200 |}} |
| Brand Name | Multaq® |
| Drug Class | [[cardio:arrhythmias:start|Class III Antiarrhythmic]] |
| Vaughan-Williams Class | Class III (Multichannel Blocker) |
| Primary Indication | Atrial Fibrillation / Atrial Flutter |
| QT Prolongation | Yes |
| Iodine Content | No |
| Half-Life | ~24 hours |
| Black Box Warning | Heart Failure Risk |
| FDA Approval | 2009 |
</WRAP>
</WRAP>

===== Overview =====

Dronedarone is a multichannel antiarrhythmic agent structurally related to [[cardio:arrhythmias:amiodarone|Amiodarone]] but without iodine moieties.

It is used for rhythm control in paroxysmal or persistent atrial fibrillation (AF) and atrial flutter (AFL).

Compared to amiodarone, dronedarone has fewer thyroid and pulmonary toxicities but is less effective and carries a boxed warning in patients with heart failure.

<WRAP clear></WRAP>

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===== Mechanism of Action =====

Dronedarone blocks multiple cardiac ion channels:

  * Potassium channels → ↑ action potential duration → ↑ QT interval  
  * Sodium channels  
  * Calcium channels  
  * Noncompetitive β-adrenergic receptor antagonism  

Net effects:
  * Prolonged repolarization  
  * Slowed AV nodal conduction  
  * Reduced AF recurrence  

Mechanistically similar to amiodarone but with shorter half-life and less tissue accumulation.

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===== Indications =====

  * Paroxysmal atrial fibrillation  
  * Persistent atrial fibrillation  
  * Atrial flutter  

Goal:
  * Reduce hospitalization in AF  

Not indicated for:
  * Permanent AF  
  * Ventricular arrhythmias  

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<WRAP blackbox>
===== Black Box Warning =====

Dronedarone increases risk of death in:

  * Symptomatic heart failure (NYHA Class III or IV)  
  * Recently decompensated heart failure  
  * Permanent atrial fibrillation  

Avoid in these populations.

</WRAP>

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<WRAP contra>
===== Contraindications =====

Absolute:
  * Symptomatic heart failure  
  * Permanent atrial fibrillation  
  * Second- or third-degree AV block (without pacemaker)  
  * Severe hepatic impairment  
  * QTc ≥ 500 ms  

Relative / Caution:
  * Bradycardia  
  * Electrolyte abnormalities  
  * Concomitant QT-prolonging drugs  

</WRAP>

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<WRAP details>
===== Dosing =====

  * 400 mg orally twice daily with meals  

No loading dose required.

</WRAP>

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<WRAP details>
===== Pharmacokinetics =====

Absorption:
  * Oral; increased with food  

Metabolism:
  * Hepatic (CYP3A4)  

Half-life:
  * ~24 hours  

Elimination:
  * Primarily fecal  

Shorter half-life and less tissue accumulation than amiodarone.

</WRAP>

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<WRAP details>
===== Adverse Effects =====

Common:
  * Nausea  
  * Diarrhea  
  * Bradycardia  

Serious:
  * QT prolongation  
  * Hepatotoxicity  
  * Heart failure exacerbation  

Lower risk of:
  * Thyroid toxicity (no iodine)  
  * Pulmonary fibrosis  

Compared to [[cardio:arrhythmias:amiodarone|Amiodarone]].

</WRAP>

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<WRAP details>
===== Drug Interactions =====

CYP3A4 inhibitors (↑ levels):
  * Azoles  
  * Macrolides  
  * Protease inhibitors  

QT-prolonging agents:
  * Fluoroquinolones  
  * Other Class III antiarrhythmics  

Digoxin:
  * Increases digoxin levels  

Warfarin:
  * May increase INR  

</WRAP>

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<WRAP monitoring>
===== Monitoring =====

  * ECG (QT interval)  
  * Liver function tests  
  * Heart failure symptoms  
  * Electrolytes  

Discontinue if patient develops permanent AF.

</WRAP>

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<WRAP pearls>
===== Clinical Pearls =====

  * Structurally similar to amiodarone but lacks iodine.  
  * Less effective than amiodarone.  
  * Fewer thyroid and pulmonary toxicities.  
  * Contraindicated in symptomatic heart failure.  
  * Not used for ventricular arrhythmias.  

</WRAP>

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===== Comparison Within Class =====

Compared to [[cardio:arrhythmias:amiodarone|Amiodarone]]:
  * Less effective  
  * Fewer organ toxicities  
  * Shorter half-life  

Compared to [[cardio:beta_blockers:sotalol|Sotalol]]:
  * Multichannel blockade vs β-blocker + K channel block  
  * No renal dosing requirement  

Compared to [[cardio:arrhythmias:dofetilide|Dofetilide]]:
  * No inpatient loading required  
  * Lower torsades risk  

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===== Related =====

  * [[cardio:arrhythmias:start|Arrhythmias]]
  * [[cardio:arrhythmias:amiodarone|Amiodarone]]
  * [[cardio:beta_blockers:sotalol|Sotalol]]
  * [[cardio:arrhythmias:dofetilide|Dofetilide]]