Last reviewed 2026-04-22 · How we verify

Flecainide controlled release

Flecainide is a Class IC antiarrhythmic that blocks cardiac sodium channels to slow conduction velocity and suppress abnormal electrical activity in the heart.

Flecainide is a Class IC antiarrhythmic that blocks cardiac sodium channels to slow conduction velocity and suppress abnormal electrical activity in the heart. Used for Paroxysmal supraventricular tachycardia (PSVT), Paroxysmal atrial fibrillation, Ventricular arrhythmias.

At a glance

Mechanism of action

Flecainide inhibits the fast inward sodium current in cardiac tissue, which decreases the rate of depolarization and slows conduction through the atria and ventricles. This action suppresses ectopic activity and stabilizes the electrical properties of the myocardium. The controlled-release formulation provides sustained drug levels to maintain antiarrhythmic efficacy over an extended dosing interval.

Approved indications

• Paroxysmal supraventricular tachycardia (PSVT)
• Paroxysmal atrial fibrillation
• Ventricular arrhythmias

Common side effects

• Dizziness
• Dyspnea
• Palpitations
• Chest pain
• Tremor
• Blurred vision
• Proarrhythmic effects (new or worsened arrhythmias)

Key clinical trials

• Flecainide Safety in Patients With Coronary Artery Disease and Atrial Fibrillation (PHASE4)
• Assessing the Neurological Outcomes After Atrial Fibrillation Ablation for Rhythm Control
• Effect and Safety of Flecainide and Metoprolol Versus Metoprolol Alone to Suppress Ventricular Arrhythmias in Arrhythmic Mitral Valve Prolapse (PHASE3)
• Pulmonary Vein Isolation With Versus Without Continued Antiarrhythmic Drugs in Persistent Atrial Fibrillation (NA)
• To Evaluate the Impact of Oral Flecainide on Quality of Life in Patients With Paroxysmal Atrial Fibrillation (PHASE4)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.