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

NCT ID: NCT01474460

Last Updated: 2017-03-09

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 370 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2011-09-30
• Study Completion Date: 2015-11-30

Brief 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.

Detailed Description

See above.

Conditions

Coagulation Delay

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: NONE

Study Groups

Control group

The control group only receiving warfarin therapy (individualized therapy, hence no specific form, dosage, frequency and duration is applicable here - i.e. 5mg daily everyday for 6 months may be applicable to one patient but not all researched patients).

Group Type: PLACEBO_COMPARATOR

phytonadione

Intervention Type: DIETARY_SUPPLEMENT

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

Phytonadione

Patients receiving 200mcg of phytonadione.

Group Type: EXPERIMENTAL

phytonadione

Intervention Type: DIETARY_SUPPLEMENT

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

Interventions

phytonadione

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

Intervention Type: DIETARY_SUPPLEMENT

Other Intervention Names

Vitamin K; Coumadin

Eligibility Criteria

Inclusion Criteria

• Be eighteen years of age and older
• Have a long-term indication for warfarin (will need to be on warfarin for 6 months or longer)
• Be a new patient on warfarin therapy, or a patient previously on warfarin therapy who has been taken off therapy for more than 2 weeks and needs to be titrated again
• Anticipate receiving medical care at the study site for the duration of the study
• Have transportation to and from the JAHVA
• Have read and signed the Informed Consent document after the study has been fully explained and has had all questions answered

Exclusion Criteria

• Have liver or kidney failure
• Are on hemodialysis or peritoneal dialysis
• Are pregnant or planning to become pregnant
• Have Alzheimer's disease, cognitive impairment, or visual impairment
• Are not compliant with medications
• Are participating in another study
• Have scheduled surgery or are planning to undergo major surgery
• Cannot be reached by telephone
• Take over-the-counter vitamin K supplementation except multivitamins

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

James A. Haley Veterans Administration Hospital

FED

Sponsor Role: lead

Responsible Party

To-Nga Huynh, PharmD.

Anticoagulation Clinical Pharmacist

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

To-Nga Huynh, PharmD

Role: PRINCIPAL_INVESTIGATOR

James A. Haley VA Hospital

Locations

James A. Haley VA Hospital

Tampa, Florida, United States

Countries

United States

Other Identifiers

Pro00000493

Identifier Type: -

Identifier Source: org_study_id