Multaq (Dronedarone)

Multaq (dronedarone) is used to manage cardiac rhythm disorders within the atrial arrhythmia family.

• Atrial fibrillation (paroxysmal): reduces the frequency of recurrent AF episodes and helps maintain sinus rhythm in patients with intermittent arrhythmia.
• Atrial fibrillation (persistent): supports rhythm control after cardioversion in patients with continuous AF, decreasing the need for repeat procedures.
• Atrial flutter: assists in preserving sinus rhythm and lowers the risk of recurrent flutter episodes following conversion.
• Atrial fibrillation (post‑ablation): contributes to sustained sinus rhythm after catheter ablation, improving long‑term procedural success.

• Dronedarone blocks multiple cardiac ion channels, including the rapid component of the delayed rectifier potassium current (I_Kr), sodium (I_Na) and L‑type calcium (I_CaL) currents, while also exerts anti‑adrenergic activity. This combined effect prolongs the action potential duration and refractory period, stabilising myocardial excitability and preventing re‑entrant circuits that trigger atrial fibrillation and flutter. Overall, the multi‑channel blockade reduces abnormal automaticity and improves rate control.

Dronedarone may cause a range of adverse reactions, varying from mild to severe.

Common Side Effects

• Nausea: mild gastrointestinal upset often occurring early in therapy.
• Diarrhea: loose stools that may be transient.
• Headache: mild to moderate intensity.
• Dizziness: sensation of light‑headedness, especially on standing.

Serious or Rare Side Effects

• Liver injury: elevated transaminases or hepatitis requiring monitoring.
• Severe skin reactions: Stevens‑Johnson syndrome or toxic epidermal necrolysis.
• Heart failure exacerbation: worsening symptoms in patients with compromised cardiac function.

Before prescribing Multaq, clinicians should consider several precautionary measures to minimise risk.

• Monitor liver function: obtain baseline and periodic liver enzyme tests during therapy.
• Assess cardiac status: avoid use in patients with NYHA class IV heart failure or severe left ventricular dysfunction.
• Evaluate renal function: dose adjustment may be needed in significant renal impairment.
• Pregnancy and lactation: contraindicated in pregnancy (category D) and not recommended while breastfeeding.
• Store at ambient temperature: keep below 25 °C, protect from moisture and light in the original packaging.

Dronedarone interacts with several medicines; understanding the interaction level guides safe co‑administration.

Major Interactions (Avoid)

• Amiodarone: combined use increases risk of hepatic toxicity and severe bradycardia.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin): raise dronedarone plasma concentrations, heightening adverse effects.
• QT‑prolonging agents: additive effect may precipitate dangerous arrhythmias.

Moderate Interactions (Monitor Closely)

• Warfarin: dronedarone may increase INR, requiring more frequent coagulation monitoring.
• Digoxin: plasma levels can rise, necessitating dose adjustment and serum level checks.
• CYP3A4 substrate statins (e.g., simvastatin): increased exposure may raise risk of myopathy; consider dose reduction.