The Association of Warfarin Dosage and Plasma Enantiomer Concentration With the Gene Polymorphisms of CYP and VKOR

NCT00247702 | Unknown

• 1 other identifier: 940609
• Study Type: interventional
• Target: 120
• Locations: 1 country
• Sites: 1

Brief Summary

Oral warfarin anticogulation for the prevention and treatment of patients with venous thromboembolism is one of the most used therapies in clinical practice. Patients require different dosage to achieve the target therapeutic anticoagulation. Optimal dosage and bleeding complication are two most clinical concerns. Besides of multiple individual factors (e.g. age, dietary intake, vitamin supplement, drug compliance etc.), some genetic factors may determine the drug requirement and safety. The cytochrome P450 CYP2C9 is a liver enzyme required for the oxidative metabolism of warfarin. The vitamin K epoxide redutase (VKOR) is a liver enzyme associated with the reuse of the oxidative hydroquinone form of vitamin K. The VKOR enzyme is the target of warfarin. Recent studies revealed both genes may determine the pharmacodynamic of warfarin anticogualation. To date, there are more than thirteen identified polymorphism at CYP2C9 gene. Majority of those variant polymorphisms may decrease the warfarin requirement. The VKOR complex subunit 1 (VKORC1) is a newly identified gene. Some polymorphisms also were reported. As we know, the Chinese patients need a lower dosage of warfarin in comparison with the Caucasian patients. We are interested in finding the genetic causes of Taiwneses Chinese patients. In our study we will first identify the polymorphism patterns of these two genes in normal population. Then, we will try to find the association between these polymorphism and patient warfarin requirement. Our pharmacogenetics study will be valuable for prevention of bleeding complication of warfarin treatment in Chinese population.

Conditions

Deep Venous Thromboembolism

Keywords

CYP2C9; VKORC1; polymorphism; warfarin

Interventions

warfarin DRUG

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Use warfarin therapy for at least two months before study
• Stable INR value during recent three months

You may not qualify if:

• higher age(\>80 y/o)
• liver and renal dysfunction
• alcohol abuse
• BMI\<18kg/m2
• coadministered medicine that can affect pharmacokinetics or pharmacodynamics of warfarin

Sponsors & Collaborators

• National Taiwan University Hospital: lead

Study Sites (1)

National Taiwan University Hospital

Taipei, 100, Taiwan

RECRUITING

MeSH Terms

Conditions

Vitamin K-Dependent Clotting Factors, Combined Deficiency Of, Type 2

Interventions

Warfarin

Intervention Hierarchy (Ancestors)

4-Hydroxycoumarins; Coumarins; Benzopyrans; Pyrans; Heterocyclic Compounds, 1-Ring; Heterocyclic Compounds; Heterocyclic Compounds, 2-Ring; Heterocyclic Compounds, Fused-Ring

Study Officials

• Tasy Wei, Doctor

  National Taiwan Univerisity Hospital

  STUDY CHAIR

Central Study Contacts

Tsay Wei, Doctor

CONTACT

886-2-23123456; woei@ha.mc.ntu.edu.tw

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER

Study Record Dates

• First Submitted: November 1, 2005
• First Posted: November 2, 2005
• Study Start: July 1, 2005
• Study Completion: June 1, 2006
• Last Updated: November 2, 2005

Record last verified: 2005-07

Locations

TW (1)