title: Bretylium tosylate: a newly available antiarrhythmic drug for ventricular arrhythmias.
abstract: Bretylium tosylate (Bretylol) has recently been approved for parenteral use against resistant ventricular arrhythmias. The pharmacologic action of bretylium is complex, and its antiarrhythmic action differs significantly from other drugs. Bretylium is an adrenergic neuronal blocking agent taken up selectively at peripheral adrenergic nerve terminals, where it initially releases norepinephrine (sympathomimetic effect) and then produces adrenergic neuronal blockade. It has direct cardiac membrane effect to prolong action potential duration and effective refractory period but, unlike other membrane active antiarrhythmic agents, does not depress conduction velocity or automaticity. Bretylium increases ventricular fibrillation threshold and prevents the decrease in ventricular fibrillation threshold associated with myocardial ischemia. It does not depress myocardial contractility. Clinical studies have shown parenteral bretylium to be effective in suppressing ventricular arrhythmias, particularly recurrent, drug resistant ventricular tachycardia or ventricular fibrillation.
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000320:Adrenergic Fibers / Q000187:drug effects; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000188:drug therapy*; D001949:Bretylium Compounds / Q000627:therapeutic use*; D001950:Bretylium Tosylate / Q000008:administration & dosage / Q000009:adverse effects / Q000378:metabolism / Q000627:therapeutic use*; D004341:Drug Evaluation; D004347:Drug Interactions; D004351:Drug Resistance; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D007263:Infusions, Parenteral; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D009200:Myocardial Contraction / Q000187:drug effects; D009203:Myocardial Infarction / Q000150:complications; D014677:Pharmaceutical Vehicles; D011690:Purkinje Fibers / Q000187:drug effects; D011802:Quinidine / Q000009:adverse effects / Q000627:therapeutic use; D013564:Sympathetic Nervous System / Q000187:drug effects*; D013610:Tachycardia / Q000188:drug therapy; D014693:Ventricular Fibrillation / Q000188:drug therapy
chemical_list: D001949:Bretylium Compounds; D014677:Pharmaceutical Vehicles; D001950:Bretylium Tosylate; D011802:Quinidine