Does Low Dose Oral Vitamin K Improve International Normalized Ratio (INR) Stability?

• Status: Completed
• Trial end date: 2014-04-01
• Target enrollment: 0
• Participant gender: All

Summary

Warfarin is highly effective for the prevention of both first and recurrent thrombotic events, however even minor excursions outside the reference INR range of 2.0 to 3.0 are associated with bleeding or thrombotic complications. The importance of maintaining the INR within the desired interval has led to the concept of "time in therapeutic range (TTR)" - the total proportion of time that the INR is between 2.0 and 3.0. The investigators propose a multicentre, double blind, randomized trial which will determine if 0.150 mg of oral vitamin K increases time in the therapeutic range for patients receiving warfarin.

• Phase: Phase 3
• Accepts Healthy Volunteers?: No

Details

• Lead Sponsor: St. Joseph's Healthcare Hamilton
• Collaborators: McMaster University; University of Western Ontario, Canada
• Treatments: Vitamin K; Vitamin K 1; Vitamins; Warfarin

Criteria

Inclusion Criteria:

• Warfarin therapy administered to a target INR of 2.0 to 3.0

Exclusion Criteria:

• Out of range INR on day of screening - enrolment will only occur if the patient's INR on the day of screening is between 1.8 and 3.4 (inclusive) - if the INR is outside this range the patient will be re-screened when the INR is within this range.

• Recent warfarin initiation - all patients must have received warfarin for a minimum of 3 months

• Planned termination or extended temporary interruption of warfarin within 6 months or anticipated survival of less than 6 months

• Known severe liver disease, known excess alcohol consumption , known malabsorption syndrome or inability to take oral medications

• Use of medications known to interfere with warfarin and whose dose is likely to change over the course of the study (e.g. barbiturates, rifampin etc.)

• Known allergy to vitamin K

• Inability or unwillingness to follow study procedures or provide consent

• Prior participation in this study, or participating in a competing study which may impact INR control