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Warfarin dose requirements in a patient with the CYP2C9*14 allele

Yee Ming Lee1, Jessica Eggen, Vinay Soni

  • 1Department of Pharmacy Practice, University of Illinois at Chicago, Chicago, IL 60612-7230, USA.

Pharmacogenomics
|June 24, 2014
PubMed

Insights

This case study examines genotype-guided warfarin dosing in a patient with atrial fibrillation and acute stroke. The rare CYP2C9*14 genotype influenced warfarin dose requirements, adding to limited clinical data.

Area of Science:

  • Pharmacogenomics
  • Cardiology
  • Internal Medicine

Background:

  • Warfarin is a common anticoagulant used for atrial fibrillation and stroke.
  • Genotype-guided warfarin dosing aims to optimize therapeutic outcomes.
  • The CYP2C9*14 allele is a rare genetic variant impacting warfarin metabolism.

Observation:

  • A 64-year-old male of Indian descent with atrial fibrillation received genotype-guided warfarin therapy post-stroke.
  • Genetic testing revealed a rare CYP2C9*1/*14 genotype, along with VKORC1 -1639GG and CYP4F2 433Met/Met genotypes.
  • The patient received a standard warfarin loading dose followed by a daily maintenance dose.

Findings:

  • Therapeutic international normalized ratio (INR) was achieved on day 5 and maintained.
  • This case provides limited but valuable data on the clinical impact of the CYP2C9*14 allele on warfarin dose requirements.
  • The patient's genetic profile suggests potential warfarin resistance.

Implications:

  • Understanding rare CYP2C9 variants like *14 is crucial for personalized warfarin therapy.
  • Pharmacogenetic testing can guide warfarin dosing, especially in patients with unusual genetic profiles.
  • Further research is needed to elucidate the precise effects of CYP2C9*14 on warfarin pharmacokinetics and pharmacodynamics.

Keywords:
CYP2C9*14VKORC1anticoagulationpharmacogeneticswarfarin

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