Experimental anti-arrhythmic properties of melperone, a neuroleptic butyrophenone.

The neuroleptic butyrophenone, melperone, has been compared with antiarrhythmics, neuroleptics, alpha-blockers and beta-blockers in various experimental arrhythmias. Melperone 0.01--1 mg/kg intravenously antagonized ouabain-induced arrhythmias in conscious rabbits to the same degree as propranolol 2 mg/kg and quinidine 10 mg/kg intravenously probably mainly via s CNS depressive effect. It was found to be considerably weaker than propranolol 2 mg/kg, when anaesthetized guinea pigs were used. Melperone 0.1--10 mg/kg was inactive against aconitine-induced arrhythmias. Melperone 1--5 mg/kg antagonized adrenaline-induced arrhythmias in halothane-sensitized guinea pigs like phentolamine 1--5 mg/kg intravenously and was more potent than chlorpromazine, propranolol and quinidine. This study and an electrophysiological study suggest that melperone might be a type III anti-arrhythmic drug, which at the same time depresses CNS and reduces afterload.