Comparison of the duration of action of pindolol and slow release oxprenolol in healthy volunteers.

The duration and extent of the reduction of exercise-induced tachycardia, as a measure of cardiac beta-adrenoceptor blockade were studied in 12 healthy volunteers after administration of single oral doses of pindolol 15 mg (Visken) or 160 mg slow release oxprenolol (Slow-Trasicor). The mean maximum effect was reached after 1.6 +/- 0.3 h with pindolol and after 2.5 +/- 0.2 h with slow release oxprenolol. The reduction in heart rate during exercise was virtually identical after both drugs, amounting to -36.1 +/- 1.7 beats/min after pindolol and -36.3 +/- 1.6 beats/min after slow release oxprenolol. The duration of action of pindolol, however, was clearly longer than that of slow release oxprenolol: after 24 h pindolol still exerted 39.6 +/- 5.6% of its maximum activity, as against 22.1 +/- 3.6% for slow release oxprenolol.