Mechanism of action
The exact mechanisms of the antifibrillatory and antiarrhythmic actions of bretylium are not established Bretylium is an adrenergic neuronal blocking agent that has both adrenergic and direct myocardial effects. Although the antidysrhythmic action of bretylium is poorly understood, like Lidocaine, it has been found to be effective in the treatment of ventricular fibrillation and ventricular tachycardia. Bretylium produces a prompt increase in ventricular fibrillation threshold, perhaps through postganglionic adrenergic blockade.