Abbreviated tacrolimus area-under-the-curve monitoring for renal transplant recipients

The area under the concentration time curve (AUC) for oral tacrolimus (FK) may provide a more precise model for FK monitoring after renal transplantat ion. The purpose of this study is to identify a simple, cost-effective meth od for predicting FK AUG. FK concentrations were measured at 0, 1,2, 4, 6, 8, and 12 hours after the morning dose. The predicted AUCs (AUC(p)s) derive d from regression equations were used to estimate the actual 12-hour AUCs ( AUC(12)S) The relationship between AUG, and AUC(12) was validated by determ ining the coefficient of multiple determination (Re), percentage of predict ion error (PE%), and percentage of absolute prediction error (APE%). Eighte en stable Oriental renal transplant recipients (9 men, 9 women) with a mean age of 42.6 +/- 6 years and mean body weight of 62.7 +/- 10 kg were recrui ted for the study. The FK AUC(12) trough, P-hour, and 4-hour concentrations were 125 +/- 24 h ng/mL (range, 87.7 to 181.9 h ng/mL), 6 1: 1.3 ng/mL, 18 .1 +/- 4.7 ng/mL, and 11 +/- 2.4 ng/mL, respectively. Trough FK concentrati on did not have a significant correlation with AUC(12) (r = 0.34; P = 0.17) . AUC(p) obtained by a two-time point regression equation using P-hour (C2) and 4-hour (C4) FK concentrations: (AUCp = 16.2 + 2.4(*)C2 +/- 5.9(*)C4) o btained an R-2, PE%, and APE% of 0.93, -0.2X +/- 5.2% (range, -13% to 9.3%) , and 3.6% +/- 3.7% (range, 0.02% to 13%), respectively. We conclude that a two-point sampling method using C2 and C4 may be a more cost-effective FK monitoring strategy than morning FK trough levels in transplant recipients. (C) 2000 by the National Kidney Foundation, Inc.