Effects of voriconazole on pharmacokinetics of tacrolimus in renal transplantation patients
Objective To explore the effects of oral voriconazole(VRC)on the pharmacokinetics of tacrolimus(TAC)in renal transplant patients.Methods Renal transplant patients who had taken TAC orally for more than 2 days and achieved steady-state plasma concentration before taking VRC.The trough concentration of TAC was measured on the 3rd,5th and 10th days after VRC 200 or 400 mg·d-1 administration.The trough concentration(C0)of TAC was determined by high performance liquid chromatography.The genotypes of TAC were determined by polymerase chain reaction and the pharmacokinetics of TAC after combined use of VRC were compared.Results After the use of VRC,the TAC C0 of 11 renal transplant patients was 3-8 μg·L-1,and the concentration of TAC ranged from 50.00%to 87.50%of the original dose.Additionally,the impact of VRC on TAC varied significantly among individuals.The mean TAC C0 value after VRC administration was significantly higher than the value before VRC[(12.14±3.89)vss(5.20±2.79)μg·L-1].Eleven renal transplant patients were grouped according to cytochrome P450(CYP)2C19-CYP3A5 gene polymorphism,under the condition of combined administration,the C0/dose of TAC in the slow metabolizer group was higher than that in the fast metabolizer group on the 3rd,5th and 10th days[(582.10±252.30)vs(439.03±166.08),(873.71±449.22)vs(666.60±168.00),(852.10±505.73)vs(261.50±81.98)μg·L-1·mg-1·kg;all P<0.01].Conclusion TAC pharmacokinetics was significantly affected by the VRC in renal transplant recipients,and the principle that TAC dose needed to be reduced by one-third of the original dose was no longer applicable,which may be related to the pharmacokinetics of the VRC itself and the gene polymorphism of CYP2C19/CYP3A5 enzyme.It is recommended to regularly monitor the concentration of TAC when VRC and TAC are used in combination.