title: Retrospective and prospective analyses of the treatment of overanticoagulated patients.
abstract: OBJECTIVE
  To compare withholding warfarin therapy with low-dose (2.5 mg) oral vitamin K therapy in excessively anticoagulated patients without bleeding complications.
  
  
  METHODS
  Prospective and retrospective studies.
  
  
  METHODS
  Anticoagulation clinic at a Veterans Affairs institution.
  
  
  METHODS
  Twenty-eight men were matched according to initial international normalized ratio (INR) and INR goal ranges.
  
  
  METHODS
  The retrospective arm of the study consisted of chart reviews of overanticoagulated patients whose warfarin doses were held until therapeutic INR values were reached. The prospective arm included overanticoagulated patients who were administered a single 2.5-mg dose of oral vitamin K.
  
  
  RESULTS
  Mean days to therapeutic INR values were 2.3+/-0.6 and 1.4+/-0.6 (p=0.001), and mean reduction in INR 1 day after treatment intervention was 1.32+/-0.79 and 3.46+/-1.31 (p<001) U for the withholding and vitamin K groups, respectively.
  
  
  CONCLUSIONS
  Compared with withholding the warfarin dose, administration of 2.5 mg of oral vitamin K to excessively anticoagulated patients receiving warfarin significantly reduced the time required to reach a therapeutic INR as well as final INR.
authors.affiliation: Veterans Affairs San Diego Healthcare Systems, California 92161, USA.
authors.forename: T M
authors.initials: TM
authors.lastname: Duong
authors.forename: B K
authors.initials: BK
authors.lastname: Plowman
authors.forename: A P
authors.initials: AP
authors.lastname: Morreale
authors.forename: K
authors.initials: K
authors.lastname: Janetzky
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage*; D001777:Blood Coagulation / Q000187:drug effects*; D001778:Blood Coagulation Disorders / Q000517:prevention & control; D006490:Hemostatics / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D014812:Vitamin K / Q000008:administration & dosage / Q000627:therapeutic use; D014859:Warfarin / Q000008:administration & dosage
chemical_list: D000925:Anticoagulants; D006490:Hemostatics; D014812:Vitamin K; D014859:Warfarin