A pharmacodynamic and pharmacokinetic comparison of pindolol 20 mg retard and a conventional tablet

In 10 healthy volunteers the time course of cardiac beta-adrenoceptor blocking activity, plasma levels and cumulative urinary excretion of pindolol were compared during a 4-day course of pindolol 5 mg (Visken) t. d. s., and one tablet of pindolol 20 mg retard (Visken retard) once a day. After oral administration of the 20 mg retard tablet, plasma concentrations of pindolol higher than half the maximum value (1/2 Cp (tmax)) were maintained about 2.5 times as long as after administration of the conventional 5 mg tablet. This is evidence for an important and marked retardation of drug release. During treatment with pindolol 20 mg retard once daily, cardiac beta-adrenoceptor blockade, measured by the reduction in exercise-induced tachycardia and in the exercise-induced rise in systolic blood pressure, at almost all times throughout the 24 h period was at least as great as during treatment with pindolol 5 mg t. d. s. This suggests that patients successfully treated with pindolol 5 mg t. d. s. can be maintained with the same beta-adrenoceptor blockade by a single tablet of pindolol 20 mg retard once daily.