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Chest. 1998 Dec;114(6):1546-50.

Prospective evaluation of anticoagulant reversal with oral vitamin K1 while continuing warfarin therapy unchanged.

Author information

1
Department of Medicine, Santa Clara Valley Medical Center, San Jose, CA, USA.

Abstract

STUDY OBJECTIVES:

To study the efficacy and safety of partially correcting therapeutic anticoagulation by administering oral vitamin K1.

DESIGN:

Prospective interventional trial.

SETTING:

Outpatient anticoagulation clinic.

PATIENTS:

Patients who required reversal of their normal or excessive therapy with oral anticoagulant drugs were recruited.

INTERVENTIONS:

All patients received a single oral dose of vitamin K1. The dose was calculated using a regression formula and was intended to decrease the international normalized ratio (INR) to a predetermined value. Patient follow-up continued for 8 weeks. We compared the actual change of the INR to the predicted change.

RESULTS:

Sixty-five reversals of anticoagulant therapy were initiated in the study group. Sixty-four of the 65 reversals were successful. The mean (+/-SEM) initial INR was 2.6+/-0.1 for the preprocedure patients and 8.4+/-0.5 for the excessively anticoagulated patients. The predicted change in the INR correlated with the actual change (r = 0.92, p < 0.0001). There were no thromboembolic events and only one hemorrhagic complication. The mean (+/-SEM) dose of oral vitamin K1 was 5.0+/-0.3 mg for the preprocedure patients and 10.0+/-1.0 mg for the excessively anticoagulated patients.

CONCLUSIONS:

The administration of a single oral dose of vitamin K1 is a safe and effective method for partially reversing anticoagulant therapy without disrupting the daily maintenance dose of warfarin. A reliable regression formula was developed to predict the dose of vitamin K1 needed to achieve the desired INR.

PMID:
9872186
DOI:
10.1378/chest.114.6.1546
[Indexed for MEDLINE]

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