CYP3A5 and Decreased liver function: Therefore, the aim of this study was to compare the incidence of liver dysfunction in stable liver transplant recipients, both CYP3A5 expressors and non-expressors, after conversion to once-daily expanded-release tacrolimus (Advagraf®), and to analyze the effect of the CYP3A5 genotype on the pharmacokinetics of both a twice-daily regimen and a once-daily tacrolimus formulation.