title: Warfarin sensitivity: be aware of genetic influence.
abstract: BACKGROUND
  avoidance of over anticoagulation in response to warfarin therapy would reduce risk of associated bleeding.
  
  
  METHODS
  two elderly patients with venous thromboembolism exhibited extreme anticoagulant response to warfarin. Both were noted to have variant CYP2C9 alleles, which reduce the metabolic capacity of cytochrome P450 2C9.
  
  
  CONCLUSIONS
  adverse outcomes with warfarin therapy could be explained and possibly avoided by identifying patients with variant alleles for CYP2C9 before initiation of therapy.
authors.affiliation: Department of Pharmacological Sciences, University of Newcastle upon Tyne, Newcastle Upon Tyne NE1 4LP, UK.
authors.forename: Tayyaba
authors.initials: T
authors.lastname: Khan
authors.forename: Farhad
authors.initials: F
authors.lastname: Kamali
authors.forename: Ann
authors.initials: A
authors.lastname: Daly
authors.forename: Barry
authors.initials: B
authors.lastname: King
authors.forename: Hilary A
authors.initials: HA
authors.lastname: Wynne
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D000925:Anticoagulants / Q000009:adverse effects*; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics; D065729:Cytochrome P-450 CYP2C9; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D013924:Thrombophlebitis / Q000188:drug therapy; D014859:Warfarin / Q000009:adverse effects*
chemical_list: D000925:Anticoagulants; D014859:Warfarin; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases