Flecainide
1 medicine
Flecainide is a class Ic antiarrhythmic used for certain fast heart rhythms. It is contraindicated after a heart attack or with structural heart disease, since it can itself trigger dangerous arrhythmias.
Key facts
- Flecainide is a class Ic antiarrhythmic that steadies the heart's electrical signals to control atrial fibrillation, atrial flutter and certain fast rhythms from the lower heart chambers.
- Your prescriber usually starts flecainide with heart monitoring, since the right dose depends on how your heart's rhythm responds.
- Flecainide is contraindicated after a heart attack or with structural heart disease, including heart failure, because in these hearts it can itself trigger dangerous, sometimes fatal, arrhythmias.
- Seek urgent care for fainting, a new or worsening irregular heartbeat, or chest pain.
What flecainide treats
Flecainide treats atrial fibrillation and atrial flutter, restoring or maintaining a regular heart rhythm, and is also used for some ventricular tachycardias in people with a structurally normal heart. In otherwise healthy hearts with occasional atrial fibrillation, it's sometimes prescribed as a single "pill in pocket" dose taken when an episode starts.
How flecainide works
Heartbeats are triggered by electrical signals passing through channels in heart muscle cells. Flecainide blocks sodium channels that carry these signals, slowing how fast the electrical impulse travels through the heart. This calms the abnormal, rapid firing that causes atrial fibrillation, flutter or ventricular tachycardia, letting the heart's own natural pacemaker regain control.
Before you take it
- Flecainide is not used after a heart attack or in people with structural heart disease, heart failure, or significant coronary artery disease. It can make arrhythmias worse in these hearts.
- Tell your prescriber about any other heart rhythm medicine, certain antidepressants, or drugs that raise flecainide levels, since combinations can increase toxicity.
- Kidney and liver function affect how flecainide is cleared; mention any impairment so your dose can be adjusted.
- An echocardiogram or heart scan is often done before starting, to rule out structural heart disease.
Side effects
Common effects include dizziness, visual disturbances such as seeing halos, nausea and fatigue, especially when starting treatment.
Stop and seek urgent medical care for any of these:
- A new or worsening fast or irregular heartbeat.
- Fainting or loss of consciousness.
- Chest pain or shortness of breath.
Safety essentials
- Flecainide's proarrhythmic risk is highest in damaged hearts. Never take it after a heart attack or with known structural heart disease, and tell every prescriber about your heart history.
- Regular ECG checks and, sometimes, blood level monitoring help keep the dose in a safe range.
- Report any new palpitations, dizziness or fainting promptly, since these can signal the dose needs adjusting.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.