Impact of CYP3 A5 genetic polymorphism on modified releasing tacrolimus pharmacokinetics in Chinese renal transplant recipients / 中国药理学通报

ABSTRACT

Aim To investigate the impact of CYP3 A5 genetic polymorphism on modified releasing tacrolimus pharmacokinetics in Chinese stable renal transplant re-cipients. Methods Pharmacokinetics of once daily-ta-crolimus( tac-q. d. ) and twice daily-tacrolimus( tac-b. i. d. ) were determined by CLIA, CYP3A5 genotype was measured by PCR-RFLP. Each 10 patients receiv-ing tac-q. d. and tac-b. i. d. respectively were en-rolled, and each 5 patients receiving tac-q. d. were matched to poor metabolizer ( PM ) and extensive me-tabolizer ( EM ) group respectively according to CYP3A5 genotypes. Results AUC0~24 h for tac-q. d. was 1. 78 folds higher than AUC0~12 h for tac-b. i. d. , and dose-adjusted C0 was 40% lower for tac-q. d. than for tac-b. i. d. There were no significant differences for other parameters between the two groups; Cmax, AUC0~24 h and C0 were 1. 75, 1. 96 and 2. 49 folds higher for PM than for EM, and dose-adjusted Cmax, AUC0~24 h and C0 were 1. 80, 2. 34 and 2. 64 folds higher for PM than for EM. There were good correla-tions between AUC0~24 h and C0 for tac-q. d. Conclu-sion Conversion from tac-b. i. d. to tac-q. d. results in requirement of increased tacrolimus dose and detec-tion of CYP3A5 genotype, which is necessary for ensu-ring C0 in the range of therapeutic window.