Effect of Ginkgo Biloba on Phenytoin Elimination
Evaluation of the Effect of Ginkgo Biloba on Phenytoin Pharmacokinetics
Sponsor: National Institutes of Health Clinical Center (CC)
Listed as NCT00011063, this PHASE1 trial focuses on Healthy and remains completed. Sponsored by National Institutes of Health Clinical Center (CC), it has been updated 6 times since 2001, reflecting limited change activity. This study adds to the evidence base for this therapeutic area through structured, versioned documentation.
Study Description(click to expand)Gingko biloba is a complementary or alternative medication used for purported cognitive enhancing effects. Despite its widespread use there is limited data regarding potential for drug interactions. The purpose of this study is to determine the effect of administration of ginkgo for 4 weeks on single dose phenytoin pharmacokinetics. Eight healthy volunteers will take a single 500mg dose of phenytoin capsules orally with serial blood samples collected over 96 hours for determination of phenytoin pharmacokinetics. Following the pharmacokinetic study subjects will begin taking 2, 60mg capsules (120mg total) of ginkgo twice daily for 28 days. Following 28 days of ginkgo subjects will then again undergo phenytoin pharmacokinetic evaluations with blood samples obtained over 96 hours for determination of phenytoin pharmacokinetics. The ratio of geometric means for phenytoin pharmacokinetic parameter values and 90% confidence intervals about the ratio of log transformed parameter values will be calculated. Confidence intervals falling within the 80-125% range will characterize the pharmacokinetic parameter values before and after ginkgo to be equivalent.
Gingko biloba is a complementary or alternative medication used for purported cognitive enhancing effects. Despite its widespread use there is limited data regarding potential for drug interactions. The purpose of this study is to determine the effect of administration of ginkgo for 4 weeks on single dose phenytoin pharmacokinetics. Eight healthy volunteers will take a single 500mg dose of phenytoin capsules orally with serial blood samples collected over 96 hours for determination of phenytoin pharmacokinetics. Following the pharmacokinetic study subjects will begin taking 2, 60mg capsules (120mg total) of ginkgo twice daily for 28 days. Following 28 days of ginkgo subjects will then again undergo phenytoin pharmacokinetic evaluations with blood samples obtained over 96 hours for determination of phenytoin pharmacokinetics. The ratio of geometric means for phenytoin pharmacokinetic parameter values and 90% confidence intervals about the ratio of log transformed parameter values will be calculated. Confidence intervals falling within the 80-125% range will characterize the pharmacokinetic parameter values before and after ginkgo to be equivalent.
Status Flow
Change History
6 versions recorded-
Jan 2026 — Present [monthly]
Completed PHASE1
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Sep 2024 — Present [monthly]
Completed PHASE1
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Jul 2024 — Sep 2024 [monthly]
Completed PHASE1
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Jan 2021 — Jul 2024 [monthly]
Completed PHASE1
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Jun 2018 — Jan 2021 [monthly]
Completed PHASE1
▶ Show 1 earlier version
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Jan 2017 — Jun 2018 [monthly]
Completed PHASE1
First recorded
Feb 2001
Trial started
Per CT.gov start date — pre-dates our first snapshot
Eligibility Summary
No eligibility information available.
Contact Information
- National Institutes of Health Clinical Center (CC)
For direct contact, visit the study record on ClinicalTrials.gov .