Flecainide

It binds to sodium channels and slowly detaches from sodium channels.

Mechanism of action:
It is a sodium channel blocker. It suppresses phase 0 of action potential in purkinje fibers and fibers of the muscles of the heart.

Actions:
It does not affect greatly the action potential.

1. In this case, automaticity of the ectopic pacemaker is decreased by the promoted threshold potential (not by a reduction in the slope of phase 4 depolarization).
2. It causes a decreased conduction and excitability and promoted refractory period (pronounced in the depolarized tissue).

Pharmacokinetics:
It is absorbed orally and it has a half life of about 16-20 hours.

Therapeutic uses:
1. It is used in premature ventricular contractions, refractory ventricular tachycardia and supraventricular tachycardia.
2. It is used for the inhibition of sudden outburst of atrial fibrillation or flutter.

Adverse effects:
It may cause dizziness, blurred vision, anorexia, nausea, vomiting, impotence and in some cases may worsen preexisting arrhythmias.