herb · for blurry vision
Ginkgo
Improves blood flow to the retina and protects it from oxidative damage.
Say that in clinical terms
Improves retinal blood flow and provides antioxidant protection to photoreceptors and retinal ganglion cells.
How strong is the research?
In patients with early glaucoma, ginkgo produced no change over two 4-week courses.
3 papers read, 1 supporting, 1 against.
Who was studied: Studied in people with a specific form of glaucoma.
How much to take
daily
120–160 mg
Primarily studied for glaucoma and age-related macular degeneration.
Before you take it
- Increases bleeding risk when combined with warfarin; pharmacovigilance data show HR 1.38 (95% CI 1.20–1.58) vs. warfarin alone. Additive risk with antiplatelet agents (aspirin, clopidogrel) and NSAIDs.
- Discontinue at least 2 weeks before any surgical or invasive procedure due to anticoagulant and antiplatelet properties.
- Contraindicated in pregnancy: possible uterotonic effects and increased peripartum bleeding risk documented.
- In vitro CYP2C9 and CYP3A4 inhibition by biflavonoid components is confirmed; clinical pharmacokinetic studies at recommended doses (120–240 mg/day EGb761) show no significant in vivo CYP interactions. Minor effects appear only at supra-therapeutic doses (≥360 mg/day). Pharmacokinetic caution is appropriate for narrow-therapeutic-index co-medications.
- No Tolerable Upper Intake Level (UL) established by NIH ODS or IOM for Ginkgo biloba. Standardized extract (EGb761) has been used safely in trials up to 6 years at standard doses; raw ginkgo seeds and crude plant material contain ginkgotoxin (4'-O-methylpyridoxine) and carry seizure risk — standardized extract removes this compound.
- Breastfeeding safety is unknown; use during lactation is not recommended.
What we make of it
The link is dead, and the study it probably refers to was published somewhere else entirely.
The detail
The identifier we stored returns nothing. The participant count and framing match a 2003 glaucoma study, but that paper appeared in a different journal under a different identifier — so we cannot be sure what we are citing.