Effects of Garlic Supplements on Drug Metabolism

December 30, 2009 updated by: Fred Hutchinson Cancer Center

Garlic Metabolism and Cytochrome P450 Modulation

This study will determine whether garlic supplements affect the way certain drugs are processed in the body.

Study Overview

Detailed Description

Garlic supplements, which are often used to lower cholesterol and prevent cancer, are one of the most commonly used herbal products in the United States.

However, little is known about the way garlic supplements may interact with prescription medications when used simultaneously. This study will investigate four commonly used garlic supplements: garlic powder with a low content of allicin (a compound with antibacterial properties), garlic powder with a high allicin content, garlic oil, and aged garlic. The effects of these 4 garlic products on the drug-metabolizing enzyme cytochrome P450 (CYP) and a drug transporter, P-glycoprotein (Pgp) will be examined.

Participants will be randomly assigned to receive one of the four garlic supplements for 4 weeks. Drug probes of CYP and Pgp will be used to assess the in vivo activities of the substances. On the first day of garlic ingestion, blood collection will occur immediately after participants ingest their garlic supplement and 3, 4, and 6 hours after ingestion. Urine collection will occur immediately after participants' first garlic ingestion and 12, 15, and 72 hours after ingestion. Blood and urine collection will determine the concentration of the drug probes in the body, which will indicate changes in CYP and Pgp. Blood and urine tests will be repeated at the end of the study.

Study Type

Observational

Enrollment (Actual)

80

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

    • Washington
      • Seattle, Washington, United States, 98109
        • Fred Hutchinson Cancer Research Center

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

16 years to 43 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Healthy volunteers

Description

Inclusion Criteria:

  • Body mass index (BMI) between 20 and 32
  • Able to read and understand English
  • MUST LIVE WITHIN THE SEATTLE, WA AREA.

Exclusion Criteria:

  • Current use of herbal medicines other than oral contraceptives
  • History of cardiopulmonary, liver, renal or endocrine disease
  • Allergy or sensitivity to any of the drugs that will be used in the probe cocktails or the garlic supplements
  • Daily consumption of vegetables with a high allium content, including garlic, shallots, leeks, and chives
  • Pregnancy or breastfeeding

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

  • Observational Models: Case-Only
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Blood plasma and urine samples
Time Frame: 3 months
3 months

Secondary Outcome Measures

Outcome Measure
Time Frame
Blood plasma and breath samples.
Time Frame: 3 months
3 months

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Danny D. Shen, PhD, Fred Hutchinson Cancer Center

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

July 1, 2005

Study Completion (Actual)

March 1, 2009

Study Registration Dates

First Submitted

July 20, 2005

First Submitted That Met QC Criteria

July 20, 2005

First Posted (Estimate)

July 22, 2005

Study Record Updates

Last Update Posted (Estimate)

January 1, 2010

Last Update Submitted That Met QC Criteria

December 30, 2009

Last Verified

December 1, 2009

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.

Clinical Trials on Healthy

Clinical Trials on Garlic powder with high allicin content

3
Subscribe