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Use of Phytonadione to Reduce International Normalized Ratio (INR) Variability in Patients on Long-term Warfarin Therapy

NCT01474460 · Status: COMPLETED · Phase: NA · Type: INTERVENTIONAL · Enrollment: 370

Last updated 2017-03-09

No results posted yet for this study

Summary

Background: Warfarin is used as an anti-coagulant in patients at risk of developing thrombosis. It has a narrow therapeutic index necessitating close monitoring of International Normalized Ratio (INR). According to a meta-analysis, patients were in therapeutic range only 63.6% of the time. This increases the risk of bleeding or thrombosis. Various retrospective and prospective studies have looked at supplementation with phytonadione in these patients to reduce the variability of INR showing an improvement in variability. Most of these studies have only been done in a small number of patients already on warfarin therapy. This study will focus on patients newly starting warfarin therapy.

Methods: This study is a prospective, randomized, controlled trial performed at James A. Haley Veterans' Hospital (JAHVA). Patients who meet criteria and sign informed consent will receive either phytonadione with warfarin or warfarin alone. Based on a power calculation for 80%, a total of 370 patients will be enrolled (185 participants in each arm). Participants will be randomized to either intervention or control. Intervention group participants will be prescribed their usual starting dose of warfarin along with 200 mcg phytonadione by mouth daily. Control group participants will be prescribed their usual starting dose of warfarin. Both groups will follow the usual standard of care. They will come in for a follow-up INR and warfarin dose titration at least once per week until therapeutic, and then as instructed up to every 6 weeks thereafter. Both groups will participate in anticoagulation clinic activities that constitute the current standard of care. Intervention will last for a total of 6 months for each participant once enrolled.

Hypothesis:Participants in the intervention group being supplemented with 200mcg of phytonadione will spend more total time with a therapeutic INR than participants in the control group.

Conditions

  • Coagulation Delay

Interventions

DIETARY_SUPPLEMENT

phytonadione

Phytonadione 200mcg PO daily for 6 months + normal dose of warfarin and standard of care treatment

Sponsors & Collaborators

  • James A. Haley Veterans Administration Hospital

    lead FED

Principal Investigators

  • To-Nga Huynh, PharmD · James A. Haley VA Hospital

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2011-09-30
Primary Completion
2015-11-30
Completion
2015-11-30

Countries

  • United States

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT01474460 on ClinicalTrials.gov