Cardioselectivity of prenalterol and isoproterenol

Abstract

We examined the hemodynamic effects and kinetics of prenalterol, a new β-adrenoceptor agonist, in 10 normal subjects. There is some doubt whether prenelterol is selective for β1 adrenoceptors in animals; therefore, we also compared its cardioselectivity with that of the nonselective agonist, isoproterenol, with respect to heart rate (HR) and blood pressure (BP) responses after inhibition of cardiovascular reflexes with atropine, clonidine, and phentolamine. After intravenous (2.5 mg) and oral (10 mg and 100 mg) dosing, t 1 2β was 2 to 3 hr. Oral bioavailability averaged 33% and was independent of dose. Oral prenalterol, l0 mg and 100 mg, increased resting HR, systolic BP, and cardiac index b..