- ICH GCP
- US Clinical Trials Registry
- Clinical Trial NCT02376114
Ginkgo Biloba and Ocular Blood Flow in Primary Open-angle Glaucoma
The Effect of Ginkgo Biloba on Ocular Blood Flow in Primary Open-Angle Glaucoma Patients: A Double-Blind Randomized Crossover Trial
Study Overview
Status
Conditions
Intervention / Treatment
Detailed Description
Glaucoma is one of the leading causes of blindness. Glaucoma progression sometimes occurs despite apparent control of intraocular pressure. Therefore, there may be other factors involved in glaucoma progression in some patients. Evidence is mounting that glaucoma patients are more likely to have abnormal ocular blood flow and vasospasm compared to those without glaucoma. Also, a study showed that those with progressive glaucoma had decreased blood flow compared to those with stable glaucoma or healthy controls. Endothelin-1, a potent vasoconstrictor, may be involved in these blood flow abnormalities. If the dysregulation of blood flow is causally related to the progression of glaucoma, then therapies aimed at improving the regulation of blood flow may help to prevent this progression.
Ginkgo may be part of an effective treatment strategy for glaucoma because it has been shown to improve peripheral and cerebral blood flow. Other properties of Ginkgo that may aid in the treatment of glaucoma include antioxidant properties, inhibition of platelet activating factor, relaxation of smooth muscle, and neuroprotective properties. Ginkgo may be particularly useful in relaxing vasospasm. Two controlled trials have examined the effect of Ginkgo on ocular blood flow in healthy subjects. One randomized crossover trial found that 2 days of Ginkgo increased the end diastolic velocity in the ophthalmic artery compared to placebo. However, another trial found that 1 dose of Ginkgo had no significant effects on ocular blood flow parameters. In people with normal tension glaucoma, Park et al found that 4 weeks of Ginkgo increased peripapillary retinal blood flow. Two randomized controlled trials have examined the impact of Ginkgo biloba on visual field in people with normal tension glaucoma with conflicting results. Clearly, there is a need for more research on this topic.
The goal of our study was to determine whether Ginkgo biloba would result in increased ocular blood flow, reduced vasospasm, and reduced endothelin-1 levels.
Study Type
Enrollment (Actual)
Phase
- Phase 2
Contacts and Locations
Study Locations
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Quebec
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Montreal, Quebec, Canada, H1T2M4
- Maisonneuve-Rosemont Hospital
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Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
Inclusion Criteria:
- We focused this trial on vasospastic glaucoma patients because we believed that these would be the patients most likely to benefit from the ability of Ginkgo to improve blood flow.
- Patients who had been identified from previous research as being vasospastic on the Transonic Laser Doppler Flowmeter (Transonic Systems Inc., Ithaca, NY) were contacted and asked if they would like to participate in the trial.
- We recruited vasospastic patients with early or moderate primary open-angle glaucoma with a typical visual field defect with an abnormal Glaucoma Hemifield Test and a Mean Deviation worse than -2 decibels, and an optic nerve head showing retinal nerve fiber layer or neuroretinal rim loss characteristic of glaucoma.
- There was no restriction for intraocular pressure at time of diagnosis although at the time of recruitment intraocular pressure had to be effectively controlled either by ocular hypertension therapy or by surgery.
- If a patient had two eyes eligible, data from the right eye only was used.
Exclusion Criteria:
- those taking anticoagulant therapy,
- those with blood disorders or diabetes,
- women who were pregnant, planning to become pregnant, or who were breast-feeding,
- patients with a history of seizures or who were currently taking anti-convulsant medication, and
- those who could not return for 2 follow-up visits at 4 and 6 weeks.
- those patients who are already taking Ginkgo were asked if they were willing to stop for 6 weeks before the study.
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Treatment
- Allocation: Randomized
- Interventional Model: Crossover Assignment
- Masking: Double
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
---|---|
Other: Ginkgo-Placebo
Patients receive Ginkgo biloba and then placebo afterwards.
|
The Ginkgo biloba extract that was used contained 24% ginkgo flavone glycosides and 6% terpene lactones (Vitamin Research Products, Carson City, Nevada).
Patients took 60 mg of Ginkgo or a placebo twice daily by mouth for two weeks.
The placebo consisted of 40 mg of corn starch.
Ginkgo and the placebo were encapsulated to ensure identical appearance.
|
Other: Placebo-Ginkgo
Patients receive placebo and then Ginkgo biloba afterwards.
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
Change in optic nerve head blood flow in the rim region as measured with the Heidelberg Retinal Flowmeter
Time Frame: 4 weeks and 10 weeks
|
Change in optic nerve head blood flow in the rim region as measured with the Heidelberg Retinal Flowmeter
|
4 weeks and 10 weeks
|
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
Change in retinal blood flow as measured by the Canon Laser Blood Flowmeter
Time Frame: 4 weeks and 10 weeks
|
Change in retinal blood flow as measured by the Canon Laser Blood Flowmeter
|
4 weeks and 10 weeks
|
Change in ocular pulse amplitude as measured with the Pascal Dynamic Contour Tonometer
Time Frame: 4 weeks and 10 weeks
|
Change in ocular pulse amplitude as measured with the Pascal Dynamic Contour Tonometer
|
4 weeks and 10 weeks
|
Change in peripheral vasospasm as measured during the cold provocation test using the Transonic Laser Doppler Flowmeter
Time Frame: 4 weeks and 10 weeks
|
Change in peripheral vasospasm as measured during the cold provocation test as measured using the Transonic Laser Doppler Flowmeter
|
4 weeks and 10 weeks
|
Change in endothelin-1 levels as measured by an enzyme-linked immunosorbent assay kit
Time Frame: 4 weeks and 10 weeks
|
Change in endothelin-1 levels as measured by an enzyme-linked immunosorbent assay kit
|
4 weeks and 10 weeks
|
Collaborators and Investigators
Sponsor
Investigators
- Principal Investigator: Ellen Freeman, PhD, Maisonneuve-Rosemont Hospital
- Principal Investigator: Mark Lesk, MD, Maisonneuve-Rosemont Hospital
Study record dates
Study Major Dates
Study Start
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Estimate)
Study Record Updates
Last Update Posted (Estimate)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- Ginkgo and blood flow
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
product manufactured in and exported from the U.S.
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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