Abstract
Population pharmacokinetics of cyclosporine (CsA) in clinical renal transplant patients has been reported in the present study. A total of 2548 retrospective drug monitoring data points were collected from 120 renal transplant patients receiving CsA. Population modeling was performed using the NONMEM (nonlinear mixed-effect modeling) program, using a one-compartment model with first-order absorption and elimination. The final regression model for CsA clearance (CL/F) with the influence of six significant covariates, comprising postoperative days (POD), total bilirubin level (TBIL, micromolar concentration), current body weight (CBW, kilograms), age (years), concurrent metabolic inhibitors of cyclosporine (INHI), and hematocrit (HCT, percentage), has been established and expressed as CL/F = 28.5 – 1.24 · POD – 0.252 · (TBIL – 11) + 0.188 · (CBW – 58) –0.191 · (Age – 42) – 2.45 · INHI – 0.212 · (HCT – 28) (liters per hour). The values in parentheses represent the median level for each of the corresponding covariates. The population estimates for CL/F (28.5 l/h), V/F (volume of distribution, 133 l), and interpatient variability (CV% = 19.7%) for CL/F were achieved, respectively. The population model was further validated by internal and external approaches, and was demonstrated to be effective and stable. Moreover, simulation was conducted to facilitate the individualized treatment based on patient information and the final model.
Footnotes
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.105.004358.
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ABBREVIATIONS: CsA, cyclosporine; NONMEM, nonlinear mixed-effect modeling; POD, postoperative days; TBIL, total bilirubin level; CBW, current body weight; BMI, body mass index; HCT, hematocrit; INHI, concurrent metabolic inhibitors of cyclosporine; ALT, alanine aminotransferase; ALP, alkaline phosphatase; OFV, objective function value; CL/F, oral clearance; V/F, apparent volume of distribution; CI, confidence interval; ME, mean predicted error; MSE, mean squared prediction error; RMSE, root mean squared prediction error; SPE, standardized prediction error; RSE, relative standard error; OBS, observed; PRED, population model-predicted; IPRED, individual model-predicted; WRES, weighted residual; COVR, covariate.
- Received March 1, 2005.
- Accepted May 24, 2005.
- The American Society for Pharmacology and Experimental Therapeutics
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