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Daily Vitamin K in Patients on Warfarin With Unstable INRs

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00287313
Recruitment Status : Completed
First Posted : February 6, 2006
Last Update Posted : January 12, 2010
Information provided by:
University of North Carolina, Chapel Hill

Brief Summary:
The purpose of this study is to determine if daily Vitamin K supplementation stabilizes INRs in patients taking warfarin with a history of frequent dose changes or variable INRs.

Condition or disease Intervention/treatment Phase
Anticoagulants Warfarin Drug: Vitamin K Not Applicable

Detailed Description:
Consistent daily Vitamin K intake may contribute to the stabilization of INR values in patients with unstable INRs on warfarin therapy. Subjects with unstable INRs will be identified from the existing patient records of the UNC Anticoagulation Clinics. Eligible subjects will sign an informed consent form and will receive a point-of-care (POC) INR monitoring device. They will undergo 9 weeks of home INR monitoring via the POC device (with monthly clinic follow-up). They will subsequently be provided with 500 mcg Vitamin K tablets to be taken once daily. Weekly POC INR monitoring with monthly clinic follow-up will continue for an additional 8 weeks.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 15 participants
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Use of Daily Vitamin K Supplementation in Patients on Warfarin With a History of Frequent Dose Changes or Variable INRs
Study Start Date : October 2005
Actual Primary Completion Date : May 2006
Actual Study Completion Date : May 2006

Resource links provided by the National Library of Medicine

Primary Outcome Measures :
  1. Number of warfarin adjustments required in each phase
  2. Time in therapeutic, sub-, and supra-therapeutic range
  3. Variance/SD of INRs for each patient
  4. Adherence assessed by pill counts and pharmacy record review
  5. Thrombotic/bleeding episodes

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Patient of UNC Anticoagulation Clinic with INR target of 2.0-3.0 and at least 9 months on uninterrupted warfarin
  • Unstable INRs for the past 6 months, defined as a minimum number of warfarin dose changes of 3
  • Patient demonstration of proper POC device technique on 2 measurements during one teaching session with investigator
  • Age greater than or equal to 18 years

Exclusion Criteria:

  • Stroke or TIA within the previous 12 months
  • VTE within the last 3 months
  • Antiphospholipid antibody syndrome
  • Pregnant patients, since warfarin is contraindicated during pregnancy

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00287313

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United States, North Carolina
University of North Carolina at Chapel Hill
Chapel Hill, North Carolina, United States, 27599
Sponsors and Collaborators
University of North Carolina, Chapel Hill
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Principal Investigator: Stephan Moll, M.D. University of North Carolina, Chapel Hill
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Responsible Party: Stephan Moll, MD, University of North Carolina at Chapel Hill Identifier: NCT00287313    
Other Study ID Numbers: 05-MED-491
First Posted: February 6, 2006    Key Record Dates
Last Update Posted: January 12, 2010
Last Verified: January 2010
Keywords provided by University of North Carolina, Chapel Hill:
Unstable INRs
Vitamin K
Additional relevant MeSH terms:
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Vitamin K
Growth Substances
Physiological Effects of Drugs
Antifibrinolytic Agents
Fibrin Modulating Agents
Molecular Mechanisms of Pharmacological Action