ChEBI: Bretylium is a quaternary ammonium cation having 2-bromobenzyl, ethyl and two methyl groups attached to the nitrogen. It blocks noradrenaline release from the peripheral sympathetic nervous system, and is used in emergency medicine, cardiology, and other specialties for the acute management of ventricular tachycardia and ventricular fibrillation. It has a role as an adrenergic antagonist, an anti-arrhythmia drug and an antihypertensive agent.