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Published on: March 28, 2017
A case of intolerance to warfarin dosing in an intermediate metabolizer of CYP2C9
Soo-Youn Lee1, June Soo Kim, Jong-Won Kim
1Department of Laboratory Medicine, Samsung Medical Center, #50, Ilwon-dong, Kangnam-gu, Seoul 135-710, Korea.
Abstract:
We report a case of intolerance to warfarin dosing due to impaired drug metabolism in a patient heterozygous for the CYP2C9*3 allele. A 30-year-old woman with an artificial cardiac pacemaker was taking warfarin to prevent thromboembolism. This patient had an extremely elevated international normalized ratio (INR) of prothrombin time (PT) following standard doses of warfarin and experienced difficulties during the induction of anticoagulation. Genotyping for CYP2C9 revealed that this patient was an intermediate metabolizer with genotype CYP2C9*1/*3. This case suggests the clinical usefulness of pharmacogenetic testing for individualized dosage adjustments of warfarin.
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