Pharmacokinetic properties of a once-daily formulation of tacrolimus in patients with renal transplantation

The present study was designed to determine the pharmacokinetic profiles of a once-daily formulation of tacrolimus (CAS 104987-11-3; TAC-once) in patients before and after introduction of renal transplantation. Pharmacokinetic parameters for tacrolimus were almost comparable among patients receiving TAC-once before, 2 weeks after and 3 weeks after renal transplantation. Among various parameters, correlated most closely with the area under the concentration-time curve during 24 h (AUC(0-24)) (R-2 = 0.82, P < 0.001), while no consistent correlation was observed between AUC0-24 and concentrations at 2 h or 4 h, or the dose of TAC-once. The clinical outcomes such as the incidence of acute rejection, renal tissue injury and cytomegalovirus infection were evaluated during the first 3 weeks and 3 months after transplantation, and the data were compared with the historical data obtained from patients who had received the conventional twice-daily formulation of tacrolimus (TAG-twice). There were no significant differences in the incidence of such clinical outcomes between the two groups. These findings suggest that C-trough is useful for therapeutic monitoring of tacrolimus in patients receiving TAC-once. In addition, pharmacokinetics and clinical outcomes were comparable between TAC-once and TAC-twice formulations.