Use of Phytonadione to Reduce International Normalized Ratio (INR) Variability in Patients on Long-term Warfarin Therapy
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Purpose
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.
| Condition | Intervention |
|---|---|
|
Coagulation Delay |
Dietary Supplement: phytonadione Drug: none-control group |
| Study Type: | Interventional |
| Study Design: | Allocation: Randomized Endpoint Classification: Safety/Efficacy Study Intervention Model: Parallel Assignment Masking: Open Label Primary Purpose: Treatment |
| Official Title: | Use of Phytonadione to Reduce INR Variability in Patients on Long-term Warfarin Therapy |
- The primary outcome of this study is to determine the length of time in therapeutic INR range for patients given phytonadione and warfarin compared to warfarin alone [ Time Frame: 6 months ] [ Designated as safety issue: No ]
- Secondary outcomes include the number of adverse events in the form of bleeding or thrombosis for both groups. [ Time Frame: 6 months ] [ Designated as safety issue: Yes ]
| Estimated Enrollment: | 370 |
| Study Start Date: | September 2011 |
| Estimated Primary Completion Date: | September 2016 (Final data collection date for primary outcome measure) |
| Arms | Assigned Interventions |
|---|---|
|
Active Comparator: Control group
The control group only receiving warfarin therapy.
|
Drug: none-control group
none. Pts will receive normal doses of warfarin and standard of care follow-up.
Other Name: Coumadin
|
|
Experimental: Phytonadione
Patients receiving 200mcg of phytonadione.
|
Dietary Supplement: phytonadione
Phytonadione 200mcg PO daily for 6 months + normal dose of warfarin and standard of care treatment
Other Names:
|
Eligibility| Ages Eligible for Study: | 18 Years and older |
| Genders Eligible for Study: | Both |
| Accepts Healthy Volunteers: | No |
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
Contacts and Locations| United States, Florida | |
| James A. Haley VA Hospital | Recruiting |
| Tampa, Florida, United States, 33612 | |
| Contact: To-Nga Huynh, PharmD. 813-972-2000 ext 5356 To-NgaNgoc.Huynh@va.gov | |
| Contact: Carla Leto, PharmD. 813-972-2000 ext 5822 Carla.Leto1@va.gov | |
| Principal Investigator: To-Nga Huynh, PharmD. | |
| Principal Investigator: Betty Prihar, MD | |
| Principal Investigator: | To-Nga Huynh, PharmD | James A. Haley VA Hospital |
More Information
No publications provided
| Responsible Party: | To-Nga Huynh, PharmD., Anticoagulation Clinical Pharmacist, James A. Haley Veterans Administration Hospital |
| ClinicalTrials.gov Identifier: | NCT01474460 History of Changes |
| Other Study ID Numbers: | Pro00000493 |
| Study First Received: | November 15, 2011 |
| Last Updated: | December 27, 2011 |
| Health Authority: | United States: Federal Government |
Keywords provided by James A. Haley Veterans Administration Hospital:
|
warfarin phytonadione INR |
Additional relevant MeSH terms:
|
Vitamin K 1 Warfarin Vitamins Micronutrients Growth Substances Physiological Effects of Drugs Pharmacologic Actions Antifibrinolytic Agents |
Fibrin Modulating Agents Molecular Mechanisms of Pharmacological Action Hemostatics Coagulants Hematologic Agents Therapeutic Uses Anticoagulants |
ClinicalTrials.gov processed this record on June 13, 2013