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Updated: Apr 15, 2026
08:38
Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
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Clinical Pharmacogenetics Implementation Consortium (CPIC) Guidelines for CYP3A5 Genotype and Tacrolimus Dosing
K A Birdwell1,2, B Decker3, J M Barbarino4
1Division of Nephrology Department of Medicine, Vanderbilt University, Nashville, Tennessee, USA.
Clinical Pharmacology and Therapeutics
|March 25, 2015
Summary
Tacrolimus blood concentrations are lower in patients expressing CYP3A5 enzymes. This impacts achieving therapeutic levels, especially after organ or stem cell transplants. Dosing adjustments based on CYP3A5 genotype are recommended.
Area of Science:
- Pharmacogenomics
- Transplantation Medicine
- Drug Metabolism
Background:
- Tacrolimus is a critical immunosuppressant post-transplant.
- CYP3A5 enzyme expression influences tacrolimus pharmacokinetics.
- Varied tacrolimus concentrations can affect transplant outcomes.
Purpose of the Study:
- To review literature on the association between CYP3A5 genotype and tacrolimus concentrations.
- To provide tacrolimus dosing recommendations based on CYP3A5 genotype.
- To inform clinical practice for optimizing immunosuppression.
Main Methods:
- Literature review of published studies.
- Analysis of tacrolimus trough concentrations in relation to CYP3A5 expressers and non-expressers.
- Synthesis of evidence to support dosing guidelines.
Main Results:
- Individuals expressing CYP3A5 (extensive/intermediate metabolizers) show lower dose-adjusted tacrolimus trough concentrations.
- CYP3A5 non-expressers (poor metabolizers) tend to have higher concentrations.
- This difference can delay reaching target therapeutic tacrolimus levels.
Conclusions:
- CYP3A5 genotype is a significant predictor of tacrolimus dose-adjusted concentrations.
- Personalized tacrolimus dosing strategies incorporating CYP3A5 genotype are warranted.
- Updated dosing recommendations based on CYP3A5 genotype can improve treatment efficacy.
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