Antiarrhythmic properties of a neuroleptic butyrophenone, melperone, in acute myocardial infarction. A double-blind trial.

In vitro animal studies suggest melperone, a neuroleptic butyrophenone, to be a type III antiarrhythmic drug according to the classification of Vaughan Williams. It has no negative inotropic effect on cardiac muscle. A double-blind trial of 3 hours' duration was carried out with melperone and placebo in 26 patients admitted to the CCU with suspected acute myocardial infarction (AMI) and ventricular arrhythmias. Melperone, 50 mg i.v., was superior to placebo in reducing the total number of ventricular ectopic beats (VEB) as well as the number of minutes with either frequent, multifocal, R-on-T-type or runs of VEB. The reduction became statistically significant in the second treatment hour in patients with definite AMI. Melperone induced sedation and reduction of systemic BP in most of the patients. Two patients with low initial systolic BP achieved a further reduction and had BP levels below 90 mmHg. Two patients experienced minor side-effects. In conclusion, melperone administered in large i.v. doses to patients with AMI induced sedation, acute BP reduction and some reduction of ventricular arrhythmia. X