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Effects of Ginseng and Ginkgo on Drug Disposition in Man

This study has been completed.
Sponsor:
Information provided by:
National Center for Complementary and Alternative Medicine (NCCAM)
ClinicalTrials.gov Identifier:
NCT00029692
First received: January 18, 2002
Last updated: July 24, 2006
Last verified: July 2006
  Purpose

This study will assess the effects of ginseng and ginkgo on 1) cognitive function, 2) enzymes that process drugs, and 3) enzymes that may help prevent cancer.


Condition Intervention Phase
Healthy
Drug: Ginseng
Drug: Ginkgo
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Masking: Double-Blind
Primary Purpose: Treatment
Official Title: Effects of Ginseng and Ginkgo on Drug Disposition in Man

Resource links provided by NLM:


Further study details as provided by National Center for Complementary and Alternative Medicine (NCCAM):

Estimated Enrollment: 60
Study Start Date: March 2002
Estimated Study Completion Date: March 2005
Detailed Description:

Over 60 million Americans use herbal medicines; of these, one-fourth also take prescription drugs. Physicians are often unaware of herbal use and of possible drug/herb interactions in their patients. Ginseng and ginkgo, enhancers of physical and mental performance, are two of the most widely taken herbals. We propose a double-blind, randomized, prospective study of effects of ginseng and ginkgo on 1) disposition of probe drugs, 2) cognitive function, and 3) glutathione-S-transferase (GST) and quinone reductase (NQ01), enzymes implicated in chemoprevention of cancer. Probe drugs will be administered to study effects of herbs on their disposition, not for therapeutic effect. Ideal probes must be safe, well tolerated, have minimal pharmacological effect, and share known metabolic pathways with other clinically used drugs. Medically stable drug-free non-smokers will be enrolled.

During a 4-week single-blind run-in, subjects will be given a 4-drug probe cocktail: caffeine to study cytochrome P4501A2 (CYP1A2), dextromethorphan for CYP2D6, buspirone (and endogenous cortisol) for CHP3A and fexofenadine for P-glycoprotein. Losartan will be given separately for CYP2C9. These enzymes metabolize over 95% of clinically used drugs. Enzyme activities will be determined by assaying appropriate blood and urine specimens for probe drugs and metabolites. Cognitive function will be tested and blood lymphocytes collected for measuring GST and NQ01 activities. Sixty subjects will then be randomly assigned to one of 4 double-blind treatment groups of 15 each: 1) ginseng extract (Ginsana), 2) ginkgo extract (Egb761), 3) both herbs, or 4) matching placebos. Tolerability of herbs will be determined. After 6 to 8 weeks of twice daily treatment with study agents, all effect parameters will be reevaluated: probe drug pharmacokinetics, cognitive function, and GST and NQ01 in blood lymphocytes. Interactions of chronic ginseng and ginkgo with drug-metabolizing pathways and with cognitive function will thus be determined.

  Eligibility

Ages Eligible for Study:   20 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Acceptable weight and laboratory test values

Exclusion Critera:

  • Abuse of drugs, tobacco, or alcohol
  • Chronic physical complaints or serious allergies
  • Illnesses requiring chronic drug ingestion
  • Use of herbs, high-dose vitamins, or non-traditional diets
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00029692

Locations
United States, Kansas
University of Kansas Medical Center
Kansas City, Kansas, United States, 66160
Sponsors and Collaborators
  More Information

No publications provided

ClinicalTrials.gov Identifier: NCT00029692     History of Changes
Other Study ID Numbers: R01 AT000842-01
Study First Received: January 18, 2002
Last Updated: July 24, 2006
Health Authority: United States: Federal Government

ClinicalTrials.gov processed this record on July 20, 2014