A Case Report of a Patient Carrying CYP2C9*3/4 Genotype with Extremely Low Warfarin Dose Requirement.
10.3346/jkms.2007.22.3.557
- Author:
Soo Youn LEE
1
;
Myung Hyun NAM
;
June Soo KIM
;
Jong Won KIM
Author Information
1. Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul, Korea. jwonk@smc.samsung.co.kr
- Publication Type:Case Report ; Research Support, Non-U.S. Gov't
- Keywords:
Warfarin;
Cytochrome P-450 CYP2C9;
Polymorphism;
Prothrombin Time;
Pharmacogenetics
- MeSH:
Aged;
Anticoagulants/pharmacology;
Aryl Hydrocarbon Hydroxylases/*genetics;
Atrial Fibrillation/*drug therapy/*genetics;
Female;
*Genotype;
Heterozygote;
Humans;
International Normalized Ratio;
Pharmacogenetics;
Polymorphism, Genetic;
Prothrombin Time;
Warfarin/*pharmacology
- From:Journal of Korean Medical Science
2007;22(3):557-559
- CountryRepublic of Korea
- Language:English
-
Abstract:
We report a case of intolerance to warfarin dosing due to impaired drug metabolism in a patient with CYP2C9*3/*4. A 73-yr-old woman with atrial fibrilation was taking warfarin. She attained a high prothrombin time international normalized ratio (INR) at the standard doses during the induction of anticoagulation and extremely low dose of warfarin (6.5 mg/week) was finally chosen to reach the target INR. Genotyping for CYP2C9 revealed that this patient had a genotype CYP2C9*3/*4. This is the first Korean compound heterozygote for CYP2C9*3 and *4. This case suggests the clinical usefulness of pharmacogenetic testing for individualized dosage adjustments of warfarin.
