- Indications with possible efficacy:
- Indications with possible, but poorly documented efficacy:
Cerebral vascular insufficiency
Cognitive function improvement in elderly people with mild to moderate memory impairment (popular use)
Early Alzheimer's disease
Memory (popular use)
Peripheral vascular insufficiency (intermittent claudication, Raynaud's phenomenon)
Vascular or mixed dementia
- Indications with no proof of efficacy:
Acute altitude sickness
Antidepressant-induced sexual disorder
Cognitive function improvement in healthy people
Retinopathy and macular degeneration
Tinnitus of vascular origin
Vertigo of vascular origin
- Risk of Drug Interactions:
- Adverse Effects:
Part of the plant used: leaves
Ginkgo biloba is a very old tree, the last remaining member of the Ginkgoceae family. Ginkgo fossils have been found to be over two hundred million years old and the tree itself can live as long as one thousand years.
A standardized extract from the leaves of the ginkgo tree is used. It usually contains 24% flavonoid glycosides and 6% terpenoids. Flavonoid glycosides contain several compounds such as kaempferol, quercetin, and isorhamnetin and primary terpenoids are ginkgolides A, B, C, M, J, and bilobalide. Ginkgo's medicinal effects result from all these constituents, and cannot be attributed to any one particular component.
Standardized ginkgo extract is thought to positively affect the cognitive functions in two ways: by stimulating populations of nerve cells that are still functional, and by protecting nerve cells from pathologic influences. In addition to its antioxidant properties, ginkgo may also improve capillary fragility and permeability, inhibit platelet-activating factor, increase cerebral blood flow and reduce blood viscosity. It may also have other beneficial properties.
Direction of use
- Dementia (including Alzheimer's disease):
Ginkgo could slightly enhance cognitive functions but don't stop Alzheimer's disease evolution.
Used doses: 120 to 240 mg of standardized leaf extract daily, in 2 to 3 divided doses.
- Peripheral vascular insufficiency:
Ginkgo has been found effective in the treatment of intermittent claudication.
Used doses: 120 to 240 mg of standardized leaf extract daily, in 2 to 3 divided doses. Treatment should continue for at many weeks before its efficacy can be evaluated.
- Raynaud's phenomenon:
Used doses: 360 mg of standardized leaf extract per day, in 3 doses.
- Cognitive function improvement in elderly people with mild to moderate memory impairment:
Used doses: 120 mg to 160 mg standardized leaf extract daily have been used.
- Side effects
Ginkgo is not associated with any specific toxicity and is very well-tolerated. A few rare cases of gastro-intestinal upset, headaches, and bleeding have been reported. Bleeding may usually occur after months of use. Dizziness and palpitations were also reported. Allergic skin reactions may occur in some people. To avoid adverse reactions, start at lower doses and titrate to higher doses as needed.
It is recommended that patients stop taking ginkgo at least 36 hours before surgery. Ginkgo is not recommended if bleedings. Also, use it with caution if diabetes or epilepsia. Avoid its use if you are allergic to one of those product: sumac, poison ivy, mango.
Ginkgo may enhance the effects of nifedipine (Adalat) as well as antiplatelet agents and oral anticoagulants (Coumadin). Use of Ginkgo with trazodone (Desyrel) is contraindicated. Before taking ginkgo extracts, check with your pharmacist to make sure that there are no interactions with your regular medication.
- Pregnancy and lactation
Since there are no safety data available concerning its use during pregnancy and breast-feeding, pregnant and lactating women should not use ginkgo.
- Ginkgo is an extremely popular and widely used natural remedy. Many studies have concluded that ginkgo is effective in some indications. In 1995, German physicians have written more than 6 million prescriptions for standardized ginkgo leaf extracts.
In 2004, Canada adopted new regulations that control the manufacturing, packaging, labeling and importing of natural health products. The new regulations also include an adverse reaction reporting system. Products that conform to the regulation's criteria are identified with a natural product number (NPN) and can be legally sold in Canada. This number indicates that the product meets specific criteria for safety and purity, not that it is effective for any indication.
Medicinal plant contents vary naturally from plant to plant - just as fruits from the same package may vary in taste and texture. There is no standard to measure the active content of each plant. Thus, efficacy of natural products should be expected to vary from brand to brand as well as from bottle to bottle of the same brand.
For more information about the Natural Health Products Regulations, or to check if a product has been assessed, visit the Health Canada website at www.hc-sc.gc.ca/dhp-mps/prodnatur/index-eng.php.
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