[The tosylate salt form of bretylium, a quaternary ammonium salt and non-selective adrenergic neuronal blocking agent with anti-arrhythmic properties. Bretylium tosylate is selectively taken up into peripheral nerve terminals and initially causes a release of norepinephrine from sympathetic nerve endings, thereby causing a sympathomimetic effect. This is followed by a prolonged anti-adrenergic action which prevents further discharge of neurotransmitter from sympathetic nerve endings. Its myocardial effects include a prolongation of action potential as well as refractory period. This drug is used to treat and suppress ventricular arrhythmias, particularly ventricular fibrillation and ventricular tachycardia. ( NCI )] (UMLS (NCI) C0006168) =Organic Chemical; Pharmacologic Substance ; =Bretylium Compounds; bretylium =BRETYLIUM TOSYLATE 2 MG/ML; BRETYLIUM TOSYLATE 4 MG/ML; BRETYLIUM TOSYLATE 100 MG/ML; BRETYLIUM TOSYLATE 50 MG/ML;