Flecainide is a prescription medicine that belongs to a group of drugs called Class Ic antiarrhythmics. It works by slowing electrical signals in the heart to help maintain a regular rhythm, especially in people with certain fast or irregular heartbeats like atrial fibrillation or ventricular tachycardia.
It was first approved for medical use in the United States in 1985 by the U.S. FDA and is now widely used globally, including in India, under various brand names. Its introduction marked a significant step in managing life-threatening arrhythmias without the need for immediate surgery.

Doctors may give you Flecainide for:

• Atrial fibrillation or flutter – fast, uneven heartbeats from the top chambers of your heart.

• Supraventricular tachycardia (SVT) – sudden spells of very fast heartbeat starting above the ventricles.

• Ventricular arrhythmias – dangerous rhythm problems starting in the lower chambers.

This medicine helps your heart pump better and can reduce symptoms like dizziness, shortness of breath, or chest discomfort caused by irregular rhythms.

Flecainide is available in tablet form and, in some settings, as an injectable solution for hospital use.

• Typical adult dose for arrhythmia control: Usually starts from 50 mg twice daily, which may be increased gradually under a doctor’s supervision.

• Maximum daily dose: Generally does not exceed 300 mg, but the exact dose depends on the patient’s weight, kidney or liver health, and how well they tolerate the drug.

• Children: Dose is adjusted by body weight and only used under specialist supervision.

• It’s important to take Flecainide exactly as prescribed and at the same time each day to keep heart rhythm stable.

Common:

• Dizziness or lightheadedness

• Blurred or double vision

• Nausea or stomach upset

• Feeling tired

Serious (get medical help immediately):

• New or worsening irregular heartbeat

• Chest pain, shortness of breath, or fainting

• Swelling in legs or sudden weight gain

• Yellowing of skin or eyes

• Not for everyone: People with structural heart disease, prior heart attacks, or certain types of heart block should generally avoid Flecainide, as it may worsen rhythm problems.

• Risk of serious arrhythmias: In rare cases, it can cause or worsen life-threatening irregular heartbeats.

• Monitor heart function: Regular ECG (electrocardiogram) checks are essential to ensure safe dosing.

• Avoid sudden stoppage: Stopping abruptly without medical advice can lead to dangerous rhythm changes.

• Kidney and liver health: Dose adjustments may be needed for those with reduced kidney or liver function.

• Drug interactions: Medicines for high blood pressure, other antiarrhythmics, or certain antidepressants can interact with Flecainide—always share your full medication list with your doctor.

• Pregnancy and breastfeeding: Only used if clearly needed, as safety data is limited; your doctor will weigh benefits against risks.

• Lifestyle considerations: Limit caffeine and alcohol, which may trigger arrhythmias in sensitive individuals.

• Close follow-up: Regular check-ups are important, especially during dose changes, to catch any side effects early.

• Take it at the same times every day to keep the medicine level steady in your body.

• Do not stop suddenly, even if your heartbeat feels normal—this could cause dangerous rhythm changes.

• If you miss a dose, take it when you remember, unless it’s nearly time for the next dose.

• Avoid driving or heavy machinery until you know how it affects you—it may cause dizziness or blurred vision.

1. https://www.ncbi.nlm.nih.gov/books/NBK542291/

2. https://pmc.ncbi.nlm.nih.gov/articles/PMC4325304/

The drug information on this page is not a substitute for medical advice. It is meant for educational purposes only. For further details, consult your doctor about your medical condition to know if you can receive this treatment.