Retrospective and prospective analyses of the treatment of overanticoagulated patients.
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.
Duong
T M
TM
Veterans Affairs San Diego Healthcare Systems, California 92161, USA.
Plowman
B K
BK
Morreale
A P
AP
Janetzky
K
K
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
D000925:Anticoagulants; D006490:Hemostatics; D014812:Vitamin K; D014859:Warfarin