Last reviewed 2026-04-23 · How we verify

Flecainide Injectable Solution

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

Flecainide is a Class IC antiarrhythmic agent 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 works by inhibiting fast inward sodium currents 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, making it effective for treating various cardiac arrhythmias. The drug has minimal effects on repolarization, distinguishing it from Class IA and IB agents.

Approved indications

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

Common side effects

• Dizziness
• Dyspnea
• Palpitations
• Chest pain
• Tremor
• Blurred vision
• Nausea
• Proarrhythmic effects

Key clinical trials

• Flecainide Versus Amiodarone in the Cardioversion of Paroxysmal Atrial Fibrillation at the Emergency Department, in Patients With Coronary Artery Disease Without Residual Ischemia (PHASE3)

Primary sources

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