Flecainide: uses, side effects & brands

Written & medically reviewed by Dr. Sanjay Anbu, MBBS · Last reviewed 5 November 2026

Flecainide restores and maintains normal rhythm in atrial fibrillation in suitable patients. It belongs to the Antiarrhythmic (heart rhythm) group. These control abnormal heart rhythms.

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Drug type — dosing is set by your doctor

Measure	Range
Drug class	Antiarrhythmic (heart rhythm)
Type	Prescription
Dose	Individual — ask your doctor or pharmacist

What it is used for

Restoring and keeping normal rhythm in atrial fibrillation in people without structural heart disease
'Pill-in-the-pocket' use for occasional AF episodes, if advised
Some other fast heart rhythms

Common brand names

India: Flecarite, Flexid
Worldwide: Tambocor

Common side effects

Dizziness
Blurred or double vision
Nausea
Shortness of breath

Before taking it — precautions

Not used after a heart attack or in heart failure
Usually taken with a rate-slowing medicine such as a beta-blocker
Kidney and liver problems need extra care; ECGs are checked

When to see a doctor urgently

Fainting or a very fast or irregular heartbeat (urgent)
Chest pain (urgent)
New or worsening breathlessness or ankle swelling

Not a prescription — no dose shown. The right dose of flecainide depends on age, weight, kidney/liver function and the condition, so MedDroid does not show a dose here. Always get your dose from a doctor or pharmacist and the leaflet inside the pack. General educational information only.

Frequently asked questions

Why can't people with heart disease take flecainide?

In people with scarred or weak hearts it can trigger dangerous rhythms. It is for hearts that are otherwise structurally normal.

What is 'pill in the pocket'?

Some people take it only when an AF episode starts, after a doctor has tested it safely. Only do this if your cardiologist has advised it.

Why take a beta-blocker as well?

It prevents the heart racing too fast if the rhythm turns into flutter.

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Sources & further reading

Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.