Pre-dosing plasma concentrations and beta-adrenoceptor blocking effects during repeated once daily dosing with 160 mg sustained-release propranolol (Inderal LA) and 16/260 oxprenolol Oros to healthy volunteers.

Plasma drug concentrations and attenuations in sub-maximal exercise tachycardia were measured in six healthy subjects 24 h after the third and fourth doses of Inderal LA and 16/260 oxprenolol Oros administered once daily. Both drugs significantly reduced exercise heart rates relative to the placebo response, at both observation times. The mean percentage reductions on the third and fourth days were, respectively, 15.7 and 11.6% for Inderal LA compared with 18.1 and 12.2% for 16/260 oxprenolol Oros. The differences between formulations were not statistically significant. The mean plasma concentrations at 24 h on the third and fourth day were 119 and 101 ng/g for oxprenolol and 16.2 and 15.8 ng/g for propranolol.