How differences in the CYP2C9 gene change warfarin metabolism
Official title: Correlation Between Phenotypic Activity of CYP2C9 and Genetic Polymorphism in CYP2C9 and Warfarin Metabolism.
Run by Hadassah Medical Organization · NCT00162474 · Data updated 2026-11-12
This study will test whether healthy adults with different CYP2C9 gene types process warfarin differently by measuring drug metabolism after dosing.
Quick facts
| Study type | Interventional |
|---|---|
| Ages | 20 Years to 50 Years |
| Sex | All |
| Enrollment | 1000 (estimated) |
| Sponsor | Hadassah Medical Organization Academic / other |
| Locations | 1 site (Jerusalem) |
| Status | Recruiting |
| Started | September 2003 |
| Main results expected | December 2030 |
| Study ends | December 2030 |
| Registry record updated | April 21, 2026 |
| Trial ID | NCT00162474 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Healthy adults aged 20–50 years with no significant disease, not taking regular medications, and without known hypersensitivity to warfarin or phenytoin are ideal candidates.
✕Probably not a fit
People with significant medical conditions, regular prescription drug use, outside the 20–50 age range, or with allergies to the study drugs are unlikely to benefit or be eligible.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
Warfarin anticoagulant effect varies widely and CYP2C9 is a key enzyme in S-warfarin metabolism. Healthy volunteers are genotyped for CYP2C9 variants and given warfarin and phenytoin to measure in vivo metabolic activity. Investigators will compare warfarin pharmacokinetics across genotype groups and correlate the phenytoin metabolic ratio with warfarin metabolism. Participants with significant illnesses, regular drug use, or known hypersensitivity to study drugs are excluded for safety and to avoid confounding results.
Why it matters
Potential benefit: If successful, the results could help tailor warfarin dosing to a person’s CYP2C9 genotype and reduce dosing errors and bleeding risk.
How similar studies have gone: Previous research has already shown that CYP2C9 variants influence warfarin dose requirements, and this study builds on that established pharmacogenetic evidence by linking metabolism measures directly to genotype.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Age range of 20-50 years old * The absence of significant disease states Exclusion Criteria: * Known hypersensitivity to warfarin or phenytoin * Known hepersensitivity to penicillins or cephalosporins (Dicloxacillin part) * The presence of significant disease states * Regular use of drugs (including birth control pills)
Where it's running
-
Hadassah Medical Organization
Jerusalem, Israel Recruiting
Study contacts
- Principal investigator: Yoseph Caraco, MD — Hadassah Medical Organization
- Study coordinator: Yoseph Caraco, MD
- Email: caraco.yoseph@mail.huji.ac.il
- Phone: 00 972 2 6779373
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.