Dose- and time-dependent binding and kinetics of pindolol in patients with congestive heart failure.

Dose- and time-dependent pharmacokinetics and plasma protein binding of pindolol were studied in patients with idiopathic cardiomyopathy who had mild to moderate congestive heart failure. The binding and plasma concentrations of pindolol at various times following the oral administration of single 5- and 10-mg doses and multiple 10-mg doses were determined. The binding of pindolol to plasma protein was time-dependent, increasing from 26% on the first day to 31% during the third day of treatment (P less than .05); this was probably due to increased alpha-1-acid glycoprotein concentration. Analysis of the plasma concentration-time data indicated dose-independent pharmacokinetics. Pindolol pharmacokinetics were time-dependent in one patient. Absorption and elimination half-lives ranged between 0.05 to 0.6 and 1.6 to 7.2 hours, respectively.