Long-Term Pharmacokinetics of Tacrolimus in Renal Recipients - Full Text View - ClinicalTrials.gov Home Search Study Topics Glossary An evaluation of the effects of genetically determined variant metabolizing and transporting proteins involved in the disposition of the immunosuppressive drug tacrolimus in renal transplant recipients. In a five year follow-up study tacrolimus dose-corrected exposure changes significantly and the effect(s) of single nucleotide polymorphisms of the CYP3A4/CYP3A5 and MDR1 genes on the latter is assessed in this study.