PharmVar GeneFocus: CYP2C9

Clin Pharmacol Ther. 2021 Sep;110(3):662-676. doi: 10.1002/cpt.2333. Epub 2021 Jul 12.


The Pharmacogene Variation Consortium (PharmVar) catalogues star (*) allele nomenclature for the polymorphic human CYP2C9 gene. Genetic variation within the CYP2C9 gene locus impacts the metabolism or bioactivation of many clinically important drugs, including nonsteroidal anti-inflammatory drugs, phenytoin, antidiabetic agents, and angiotensin receptor blockers. Variable CYP2C9 activity is of particular importance regarding efficacy and safety of warfarin and siponimod as indicated in their package inserts. This GeneFocus provides a comprehensive overview and summary of CYP2C9 and describes how haplotype information catalogued by PharmVar is utilized by the Pharmacogenomics Knowledgebase and the Clinical Pharmacogenetics Implementation Consortium.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Alleles
  • Cytochrome P-450 CYP2C9 / genetics*
  • Haplotypes / genetics
  • Humans
  • Knowledge Bases
  • Pharmaceutical Preparations / administration & dosage
  • Pharmacogenetics / methods
  • Polymorphism, Genetic / genetics*


  • Pharmaceutical Preparations
  • Cytochrome P-450 CYP2C9