Low-dose vitamin K1 versus short-term with holding of acenocoumarol in the treatment of excessive anticoagulation episodes induced by acenocoumarol. A retrospective comparative study.

Background: No consensus exists about the management of iatrogenically induced excessive hypocoagulability episodes.

Objective: To compare the two most common therapeutic approaches in such situations (discontinuation of the oral anticoagulant vs. low-dose subcutaneous vitamin K1) when acenocoumarol is the normally used anticoagulant.

Patients and methods: The study was retrospective and comparative. Patients received antithrombotic therapy using acenocoumarol. Anticoagulant plasmatic activity was assessed through the international normalized ratio (INR) recorded from December 1994 to December 1997 at two medical centers.

Results: INR is brought faster to a safe range in patients treated with low-dose vitamin K1 (p = 0.01). Their long-term behavior is also more stable and predictable and no resistance to the oral anticoagulant was found.

Conclusion: Low-dose vitamin K1 is a safer therapeutic option compared to simply withholding the oral anticoagulant. Its best scheme of administration, however, has yet to be defined.