Generic Flecainide

Common use

Flecainide is a prescription antiarrhythmic medication used to treat and prevent certain types of serious irregular heartbeats, such as paroxysmal supraventricular tachycardia (PSVT) and atrial fibrillation. It helps the heart maintain a normal and steady rhythm by slowing electrical signals in the heart. Flecainide is typically used in patients without significant structural heart disease. It may also be prescribed for ventricular arrhythmias in specific cases.

Dosage and direction

The usual starting dose for adults is 50–100 mg twice daily, which may be adjusted based on response and tolerability. Dosage should be individualized and closely monitored through ECG and plasma level assessments. The tablets should be taken with or without food, at the same times each day. Do not stop or change your dose without medical supervision.

Precautions

Flecainide should be used with caution in patients with a history of heart failure, conduction abnormalities, or recent myocardial infarction. It may worsen certain arrhythmias or cause new ones, especially if improperly dosed or in patients with structural heart disease. Regular ECG monitoring is essential during treatment. Tell your doctor about all heart conditions or if you're pregnant, planning pregnancy, or breastfeeding.

Contraindications

Flecainide is contraindicated in individuals with second- or third-degree AV block, bundle branch block, or cardiogenic shock, unless a pacemaker is in place. It should not be used in chronic atrial fibrillation that has not been converted to sinus rhythm. Patients with known hypersensitivity to flecainide should not take this medication. It is also contraindicated in severe liver or kidney impairment without dose adjustment and monitoring.

Possible side effect

Common side effects include dizziness, visual disturbances (like blurred or double vision), and fatigue. Some people may experience headache, nausea, or shortness of breath. Serious but rare effects include new or worsened arrhythmias, heart block, or congestive heart failure. Any unusual symptoms should be reported to a healthcare provider immediately.

Drug interaction

Flecainide may interact with medications such as digoxin, amiodarone, beta-blockers, and certain antidepressants. Drugs that affect liver enzymes, like quinidine or cimetidine, may also alter flecainide levels. Combining it with other antiarrhythmic drugs can increase the risk of proarrhythmic effects. Always inform your healthcare provider of all prescription, OTC, and herbal products you are using.

Missed dose

If you miss a dose, take it as soon as you remember, unless it’s close to your next scheduled dose. In that case, skip the missed one and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. Keeping a routine or setting reminders can help maintain consistent dosing.

Overdose

An overdose of flecainide can cause life-threatening arrhythmias, low blood pressure, slowed heart rate, seizures, or cardiac arrest. Immediate emergency medical attention is required. Supportive care and monitoring in a hospital setting are typically necessary. Always store medication safely to prevent accidental overdose.

Storage

Store flecainide tablets at room temperature (20°C to 25°C / 68°F to 77°F), protected from moisture and light. Keep the container tightly closed and out of reach of children and pets. Do not use after the expiration date. Dispose of unused medication properly according to local regulations.

Disclaimer

We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis. Any specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim reliability of this information and mistakes it could contain. We are not responsible for any direct, indirect, special or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.

Clinical Verification

Last Clinically Updated: August 15, 2026

Written By

Dr. Elena Vance, PharmD

Clinical Specialist in Neuropharmacology

Fact Checked By

Marcus Thorne, MS

Biomedical Data & FDA Label Verification

Medically Reviewed By

Dr. Arthur Campbell, MD

Board-Certified Psychiatrist (ABPN)