Beta-blocking effect and pharmacokinetics of pindolol in young and elderly hypertensive patients

The pharmacokinetics and beta-blocking effect of pindolol has been compared in 20 patients with essential hypertension (WHO Stage I), 10 below 25 years of age and 10 older than 60 years. Each patient received pindolol 10 mg p.o. once a day for 5 days. The area under the curve (AUC) of pindolol was larger in the old than in the young patients both on the first (p less than 0.05) and the fifth (p less than 0.01) days. The AUC of pindolol was 14% higher on the fifth day compared to the first day in the elderly group, indicating minor accumulation at steady-state. There was no change in AUC in the young patients. Endogenous creatinine clearance was lower in the old (80 +/- 9 ml/min) than in the young patients (150 +/- 45 ml/min). The beta-blocking effect did not differ between the groups at 2 h after administration of pindolol on Days 1 or 5. However, 24 h after the first and fifth doses approximately 60% of the beta-blockade persisted in the old group whereas 17 and 19% of the beta-blockade, respectively, persisted in the young group; the difference between the groups was statistically significant (p less than 0.01). The most probable explanation for the more sustained beta-blocking effect in the elderly is the physiologically decrease in renal function, which results in a more sustained plasma level of pindolol in those patients.