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

The recruitment status of this study is unknown because the information has not been verified recently.
Verified July 2005 by National Taiwan University Hospital.
Recruitment status was  Recruiting
Sponsor:
Information provided by:
National Taiwan University Hospital
ClinicalTrials.gov Identifier:
NCT00247702
First received: November 1, 2005
Last updated: NA
Last verified: July 2005
History: No changes posted

November 1, 2005
November 1, 2005
July 2005
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No Changes Posted
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The Association of Warfarin Dosage and Plasma Enantiomer Concentration With the Gene Polymorphisms of CYP and VKOR
Study of the Association of Warfarin Dosage and Plasma Enantiomer Concentration With the Gene Polymorphisms of CYP and VKOR

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.

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Interventional
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Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Deep Venous Thromboembolism
Drug: warfarin
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruiting
120
June 2006
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Inclusion Criteria:

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

Exclusion Criteria:

  • higher age(>80 y/o)
  • liver and renal dysfunction
  • alcohol abuse
  • BMI<18kg/m2
  • coadministered medicine that can affect pharmacokinetics or pharmacodynamics of warfarin
Both
18 Years to 80 Years
No
Contact: Tsay Wei, Doctor 886-2-23123456 ext 5040 woei@ha.mc.ntu.edu.tw
Taiwan
 
NCT00247702
940609
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National Taiwan University Hospital
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Study Chair: Tasy Wei, Doctor National Taiwan Univerisity Hospital
National Taiwan University Hospital
July 2005

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP