What Is Flecainide, How Does It Work, And What Are The Side Effects?

— -- Question: I have been placed on an antiarrhythmic drug called flecainide for my heart rhythm problem. How does it work and what are the side effects?

Answer:Flecainide is a commonly used heart rhythm drug that's a potent sodium channel blocker, which is a certain channel that affects conduction in the heart.

This drug has been commercially available for almost 25 years. It has been very well-studied and it's predominately used for people that have abnormalities in the top chamber. A common heart rhythm called atrofibrillation would be the most common use of this drug.

However, the drug has other uses including treating other top chamber rhythms or some bottom chamber rhythms such as premature beats from the bottom chambers, what we premature ventricular complexes, or even what we call runs of these complexes called ventricular tachycardia.

This drug is very well-tolerated in that people feel good on it. It's very uncommon for them to have side effects. The most common side effects are headaches or sometimes blurred vision.

This drug, though, is usually restricted to patients that have very little damage to the heart. This drug can be dangerous to use if you've had a heart attack and damage to the bottom chamber. In patients like this, this drug has some propensity to worsen the arrhythmia and because of that we don't use it in patients with what we call structural heart disease -- especially if the squeeze of their bottom chamber is not good.

In deciding whether you're going to be on this medicine or not, your physician may get certain tests like an EKG or a stress test or an echocardiogram in order for him or her to determine whether you have a heart that's strong enough to take this medicine or whether you're better taking a different kind of medication.