Reversal of excessive oral anticoagulation with a low oral dose of vitamin K1 compared with acenocoumarine discontinuation. A prospective, randomized, open study.
We performed a prospective, randomized, open study in 109 outpatients under chronic anticoagulation with acenocoumarine, presenting with International Normalized Ratios (INRs) > or = 6.0 and no or minor bleeding. All the patients withheld one dose of acenocoumarine; in addition, a treated group also received 1 mg oral vitamin K1. We aimed at a post-intervention INR < 6.0, with a target zone of 2.0-4.0. The INRs were lowered from a mean of 8.1 +/- 1.7 to 4.9 +/- 2.5 in the controls (P = 0.0000) and from 8.4 +/- 2.4 to 3.3 +/- 3 in the treated patients (P = 0.0000). There were no differences in the percentage of patients with post-intervention INRs < 6.0 or within the therapeutic zone. One-third of the treated patients and only 2% of the controls reached INRs < 2.0 (P = 0.0003). Oral vitamin K1 offered no advantage to the simple discontinuation of one dose of acenocoumarine. A substantial number of treated patients were consequently exposed to under-anticoagulation.
Hemostasis and Thrombosis Department, Instituto de Investigaciones Hematológicas M. Castex, Academia Nacional de Medicina, Buenos Aires, Argentina.
C G
CG
Fondevila
S H
SH
Grosso
M T
MT
Santarelli
M D
MD
Pinto
D000074:Acenocoumarol / Q000009:adverse effects* / Q000627:therapeutic use; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use; D001779:Blood Coagulation Factors / Q000187:drug effects / Q000378:metabolism; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D010837:Vitamin K 1 / Q000008:administration & dosage* / Q000592:standards
D000925:Anticoagulants; D001779:Blood Coagulation Factors; D010837:Vitamin K 1; D000074:Acenocoumarol