Flecainide hydrochloride is a potent and orally active antiarrhythmic agent widely used in the treatment of various cardiac arrhythmias. It belongs to the class IC antiarrhythmic drugs, which are known for their strong sodium channel-blocking properties. Flecainide hydrochloride primarily works by inhibiting the cardiac fast inward sodium current (INa) and the rapid component of the delayed rectifier potassium current (IKr), leading to a prolongation of the action potential duration (APD) in both ventricular and atrial muscle fibers. Its unique electrophysiological effects make it particularly effective in managing certain types of arrhythmias, including fetal tachycardias.
