Oral vitamin K effectively treats international normalised ratio (INR) values in excess of 10. Results of a prospective cohort study.
Unanticipated elevation of the INR is common in patients receiving warfarin. We performed a prospective cohort study of 107 warfarin-treated patients with INR values of more than 10 who received a single 2.5 mg dose of oral vitamin K. During the first week, one patient experienced major bleeding, and one died. In the first 90 days after enrolment four patients had major bleeding (3.7%, 1.0% to 9.3%), eight patients (7.5%, 3.3% to 14.2%) died and two had objectively confirmed thromboembolism. Based on our low rate of observed major bleeding we conclude that 2.5 mg of oral vitamin K is a reasonable treatment for patients with INR values of more than 10 who are not actively bleeding.
Crowther
Mark A
MA
Division of Hematology and Thromboembolism, McMaster University Faculty of Health Sciences, St Joseph's Hospital, 50 Charlton Ave. East, Hamilton, Ontario, Canada. crowthrm@mcmaster.ca
Garcia
David
D
Ageno
Walter
W
Wang
Luqi
L
Witt
Dan M
DM
Clark
Nathan P
NP
Blostein
Mark D
MD
Kahn
Susan R
SR
Schulman
Sam
S
Kovacs
Michael
M
Rodger
Marc A
MA
Wells
Philip
P
Anderson
David
D
Ginsberg
Jeffrey
J
Selby
Rita
R
Siragusa
Sergio
S
Silingardi
Mauro
M
Dowd
MaryBeth B
MB
Kearon
Clive
C
D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020246:Venous Thrombosis / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D014812:Vitamin K / Q000008:administration & dosage* / Q000009:adverse effects; D014859:Warfarin / Q000008:administration & dosage* / Q000009:adverse effects
D000925:Anticoagulants; D014812:Vitamin K; D014859:Warfarin