Low dose oral vitamin K to reverse acenocoumarol-induced coagulopathy: a randomized controlled trial.
Low dose oral vitamin K rapidly reverses warfarin-associated coagulopathy. Its effect in patients receiving acenocoumarol is uncertain. We compared the effect of withholding acenocoumarol and administering 1 mg oral vitamin K with simply withholding acenocoumarol in asymptomatic patients presenting with INR values between 4.5 and 10.0. The primary end-point of the study was the INR value on the day following randomisation. We found that patients receiving oral vitamin K had more sub-therapeutic INR levels than controls (36.6% and 13.3%, respectively; RR 1.83, 95% confidence interval 1.16, 2.89) and a lower, but non-significant, proportion of INR values in range (50% and 66.6%, respectively) on the day following randomisation. After 5 +/- 1 days, there were more patients with an INR value in range in the vitamin K group than in controls (74.1% and 44.8%, respectively). There were no clinical events during 1 month follow-up. We conclude that the omission of a single dose of acenocoumarol is associated with an effective reduction of the INR in asymptomatic patients presenting with an INR value of 4.5 to 10.0. Furthermore, the use of a 1 mg dose of oral vitamin K results in an excessive risk of over-reversal of the INR.
Ageno
W
W
Department of Medicine, University of Insubria, Varese, Italy. agewal@yahoo.com
Crowther
M
M
Steidl
L
L
Ultori
C
C
Mera
V
V
Dentali
F
F
Squizzato
A
A
Marchesi
C
C
Venco
A
A
D000074:Acenocoumarol / Q000008:administration & dosage / Q000009:adverse effects*; D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects; D000933:Antifibrinolytic Agents / Q000008:administration & dosage; D001778:Blood Coagulation Disorders / Q000139:chemically induced* / Q000188:drug therapy*; D016009:Chi-Square Distribution; D004336:Drug Antagonism; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D014812:Vitamin K / Q000008:administration & dosage*
D000925:Anticoagulants; D000933:Antifibrinolytic Agents; D014812:Vitamin K; D000074:Acenocoumarol