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.
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).
It is absorbed orally and it has a half life of about 16-20 hours.
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.
It may cause dizziness, blurred vision, anorexia, nausea, vomiting, impotence and in some cases may worsen preexisting arrhythmias.