Prediction of Drug Interactions With CYP2C9 Substrates

October 28, 2008 updated by: Hadassah Medical Organization

Prediction of Potential Drug Interaction With CYP2C9 Substrate by Using Phenytoin Metabolic Ratio as a Marker of Its Activity in-Vivo.

CYP2C9, is one of the major drug metabolism enzymes accounting for about 20% of the hepatic cytochrome P450 content and being second only to CYP3A4.

The proposed study will explore different possible drug interactions with CYP2C9 substrates by evaluating the effect of prototype inducers and inhibitors on the phenotypic trait measurement. It is expected that the identification of drugs that might interact with CYP2C9 substrates will be used to rationalize future drug interaction studies designed to evaluate the actual magnitude of effect and its clinical implications. This approach should be particularly useful when applied to those CYP2C9 drugs characterized by a narrow therapeutic index (i.e. warfarin).

This study will consist of three study periods separated from each other by a two weeks washout period. In the course of the study the subjects will receive in a double blind, crossover fashion, rifampin 300 mg. twice daily, diclofenac 50 mg twice daily. and fluconazole 200 mg. twice daily, each for one week. All drugs will be administered as identical looking tablets that will be prepared at the pharmacy of the Hadassah University Hospital and their order of administration will be randomized.On the day prior to, on day 6 of and 7 days following each drug period, the activity of CYP2C9 will be evaluated by the administration of a single phenytoin 300 mg. dose. The subjects will be requested to collect their urine for 24 hours and a single blood sample will be obtained 12 hours post phenytoin intake.

Study Overview

Study Type

Interventional

Enrollment

16

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Jerusalem, Israel
        • Hadassah Medical Organization

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

20 years to 50 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Age range 20-50
  • Absence of significant disease states

Exclusion Criteria:

  • Known hypersensitivity to one of the drugs used in the study
  • Significant disease states
  • Regular use of drugs (including birth control pills)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Phenytoin metabolic ratio prior to and following exposure to fluconazole, diclophenac and rifampicin.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Investigators

  • Principal Investigator: Yoseph Caraco, MD, Hadassah Medical Organization

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

August 1, 1999

Study Registration Dates

First Submitted

September 12, 2005

First Submitted That Met QC Criteria

September 25, 2005

First Posted (Estimate)

September 27, 2005

Study Record Updates

Last Update Posted (Estimate)

October 29, 2008

Last Update Submitted That Met QC Criteria

October 28, 2008

Last Verified

October 1, 2008

More Information

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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