Cardiovascular effects of single oral doses of the new beta- adrenoceptor blocking agents betaxolol (SL 75212) in healthy volunteers.

1 The effects of betaxolol (SL 75212), a new beta-adrenoceptor blocking agent, on the cardiovascular response to exercise have been studied in six normal subjects after placebo and single oral doses of 5, 10, 20 and 40 mg given double-blind in a randomized sequence. 2 All doses reduced exercise heart rate, with a significant reduction persisting to 23 h after doses of 20 mg and 40 mg. Systolic blood pressure on exercise was reduced after all doses, with a reduction continuing to 23 h after doses of 10 mg and above. 3 The mean elimination half-life of SL 75212 was 17.5 +/- 3.9 h. The plasma clearance ranged from 0.15- 0.48 1 kg-1 h-1 and the volume of distribution from 5.8-13 1 kg-1. 4 There was a significant correlation between the peak blood levels and change in exercise heart rate (r = 0.53, P less than 0.05) and between the area under the blood concentration curve and the effect of the exercise heart rate (r = 0.55, P less than 0.01). [ABSTRACT FROM AUTHOR]