Cardiovascular pharmacology of bepridil (1[3 isobutoxy 2 (benzylphenyl) amino] propyl pyrrolidine hydrochloride) a new potential anti-anginal compound.

In dogs intravenous bepridil (2.5 mg/kg) increased coronary sinus blood flow and PVO2. Arterial pressure was briefly lowered, and heart rate was slowed in animals with intact or denervated hearts, or after propranolol administration. Ventricular inotropism was reduced at higher doses. Bepridil (5 mg/kg i.v.) showed a partial antagonist activity on isoprenaline cardiovascular effects (or cardiac sympathetic stimulation effects) i.e. tachycardia, increase in left dP/dt max. and diastolic hypotension. The antitachycardia activity was particularly pronounced. It was found to be non-competitive. It was also found to be non-specific since glucagon, theophylline- and papaverine-induced tachycardia were also reduced. The continuous infusion of high doses of bepridil did not cause any disturbance in atrio-ventricular or intraventricular conduction. In rats, after 50 mg/kg/day p.o., bepridil did not alter myocardial noradrenaline levels.