Related Experiment Video
Updated: Apr 27, 2026

Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
Pharmacogenetics of tacrolimus: ready for clinical translation?
Eliecer Coto1, Beatriz Tavira2, Beatriz Suárez-Álvarez3
1Genética Molecular, Hospital Universitario Central de Asturias , Oviedo, Spain ; Departamento de Medicina, Universidad de Oviedo , Oviedo, Spain ; Fundación Renal 'Iñigo Alvarez de Toledo' , Madrid, Spain ; Red de Investigación Renal , Redinren, Spain.
Abstract:
Tacrolimus (Tac) exhibits an interindividual pharmacokinetic variability that affects the dose required to reach the target concentration in blood. Tac is metabolized by two enzymes of the cytochrome P450 family, CYP3A5 and CYP3A4. The effect of the CYP3A5 genotype on Tac bioavailability has been demonstrated, and the main determinant of this pharmacogenetic effect is a single-nucleotide polymorphism (SNP) in intron 3 of CYP3A5 (6986 A>G; SNP rs776746; also known as CYP3A5*3). The mean dose-adjusted blood Tac concentration was significantly higher among CYP3A5*3 homozygotes than that of carriers of the wild-type allele (CYP3A5*1). In a recent prospective study, a group of kidney transplant patients received a Tac dose either according to the CYP3A5 genotype (the adapted group) or according to the standard regimen (the control group). All patients received induction therapy with mycophenolate mofetil, corticosteroids, and either basiliximab or intravenous anti-thymocyte globulin. Patients in the adapted-dose group required 3-8 days (median 6 days) to reach the target range compared with 3-25 days (median 7 days) in the control group (P=0.001). The total number of dose modifications was also lower in the adapted-dose group. This study also suggested that the CYP3A5 genotype might contribute minimally to the reduction of early acute rejection. However, additional studies are necessary to determine whether the pharmacogenetic approach could help reduce the necessity for induction therapy and co-immunosuppressors.
Related Concept Videos
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase
Pharmacogenomics: Identification of New Drug Targets
Pharmacogenetics of Phase II Enzymes: N-acetyltransferase, Thiopurine S-methyltransferase, UDP-glucuronosyltransferase
Pharmacogenetics of Drug Metabolism: Overview
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes

