Za Pharmacy
Drugs, Supplies and Delivery
Propafenone
Propafenone is a class Ic antiarrhythmic medication used to treat and prevent certain types of abnormal heart rhythms, particularly atrial fibrillation and ventricular arrhythmias. It is known for its sodium channel-blocking properties and is often used when other antiarrhythmic drugs are ineffective or contraindicated. This article synthesizes information from the British National Formulary (BNF), Lippincott Textbook of Pharmacology, and Lange Basic & Clinical Pharmacology to provide a detailed overview of propafenone, including its mechanism, uses, dosing, side effects, precautions, and drug interactions.
Propafenone is a sodium channel blocker that primarily works by:
- Inhibiting sodium influx during phase 0 of the cardiac action potential, slowing conduction velocity in the atria, ventricles, and His-Purkinje system.
- Prolonging the refractory period of cardiac tissues, which helps suppress abnormal electrical activity and restore normal rhythm (Lippincott, Lange).
Propafenone also has mild beta-blocking activity, which contributes to its antiarrhythmic effects, particularly in slowing AV nodal conduction (BNF).
- Atrial Fibrillation (AF):
- Used for the maintenance of sinus rhythm in patients with paroxysmal or persistent AF (BNF).
- Paroxysmal Supraventricular Tachycardia (PSVT):
- Effective in preventing recurrent episodes of PSVT (Lippincott).
- Ventricular Arrhythmias:
- Used to treat life-threatening ventricular arrhythmias, such as ventricular tachycardia (Lange).
- Atrial Fibrillation and PSVT:
- Initial dose: 150 mg three times daily, increased gradually to 300 mg twice daily if needed (max 900 mg/day) (BNF).
- Ventricular Arrhythmias:
- Initial dose: 150 mg three times daily, titrated to response (max 900 mg/day) (Lippincott).
Administration:
- Take with or without food.
- Regular monitoring of ECG and cardiac function is essential to detect proarrhythmic effects (Lange).
- Common: Metallic taste, dizziness, nausea, and constipation (Lippincott).
- Serious: Proarrhythmia (e.g., ventricular tachycardia, torsades de pointes), heart failure exacerbation, and bronchospasm (due to beta-blocking activity) (BNF).
- Structural Heart Disease: Avoid in patients with significant structural heart disease (e.g., ischemic heart disease, cardiomyopathy) due to increased risk of proarrhythmia (Lange).
- Heart Failure: Contraindicated in patients with uncompensated heart failure (BNF).
- Pregnancy: Use only if benefits outweigh risks; limited data available (Lippincott).
- Liver Impairment: Dose reduction may be necessary in patients with hepatic dysfunction (Lange).
- Beta-Blockers: Increased risk of bradycardia and heart failure exacerbation (BNF).
- Digoxin: Propafenone increases digoxin levels; monitor digoxin levels closely (Lippincott).
- Warfarin: Propafenone increases warfarin levels, increasing the risk of bleeding (Lange).
- CYP2D6 Inhibitors (e.g., fluoxetine, paroxetine): Increase propafenone levels, raising the risk of toxicity (BNF).
Propafenone is the generic name for this medication. It is marketed under the brand name Rythmol® in some regions. Generic versions are widely available and cost-effective.
