List of products in the National Drug Code with proprietary name . This medication is used to treat certain types of serious (possibly fatal) irregular heartbeat (such as persistent ventricular tachycardia and paroxysmal supraventricular tachycardia). It is used to restore normal heart rhythm and maintain a regular, steady heartbeat. It is also used to prevent certain types of irregular heartbeat from returning (such as atrial fibrillation). Flecainide is known as an anti-arrhythmic drug. It works by blocking certain electrical signals in the heart that can cause an irregular heartbeat. Treating an irregular heartbeat can decrease the risk for blood clots, and this effect can reduce your risk of heart attack or stroke. Older adults should discuss the risks and benefits of this medication with their doctor or pharmacist, as well as other effective and possibly safer treatments.