Ginkgo Biloba
Ginkgo biloba
Generic Name
Ginkgo biloba
Mechanism
Ginkgo biloba (standardized EGb 761) exerts its effects through a multifactorial pharmacological profile:
• Antioxidant activity – Scavenges reactive oxygen species (ROS) and protects neuronal membranes from oxidative damage.
• Improved microcirculation – Dilates capillaries, enhances oxygen delivery, and increases cerebral blood flow via nitric‑oxide modulation.
• Platelet‑activating factor (PAF) inhibition – Limits platelet aggregation and thrombus formation.
• Neurotransmitter modulation – ↓ Acetylcholinesterase activity and ↑ dopamine, norepinephrine, and serotonin levels, supporting cognitive function.
• Mitochondrial protection – Stabilizes mitochondrial membranes, preserves ATP production, and reduces apoptosis of endothelial cells.
These complementary actions collectively underpin its use in neurovascular and neurodegenerative disorders.
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Pharmacokinetics
| Parameter | Typical Finding | Notes |
| Absorption | 20–30 % of an oral dose is bioavailable; peak plasma levels within 30–120 min. | Co‑administration with food modestly delays Cmax but does not change AUC. |
| Distribution | Distributed into central nervous system; lipophilic constituents cross the blood‑brain barrier. | Limited protein binding (< 5 %). |
| Metabolism | Primarily hepatic, involving CYP3A4 and CYP1A2 for flavonol glycosides; minor glucuronidation of terpenoids. | Low potential for enzyme induction/inhibition but interactions with CYP3A4 inhibitors (e.g., ketoconazole) should be monitored. |
| Half‑life | 4–7 hr for active flavonoid glycosides; longer for sesquiterpene lactones. | Steady‑state achieved in 1–2 days at usual doses. |
| Excretion | Renal (~70 %) and biliary (~20 %) routes; metabolites are mainly sulfated or glucuronidated. | No dosage adjustment required for mild–moderate renal impairment. |
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Indications
- Cognitive Decline & Vascular Dementia – Demonstrated efficacy in improving cognition, especially where vascular pathology is prominent.
- Age‑Related Cognitive Disorders – Slows decline in mild to moderate cases.
- Peripheral Vascular Disease – Improves walking distance in intermittent claudication (in combination with exercise).
- Age‑Related Visual Impairment – Stabilizes central vision in patients with macular degeneration.
- Migraine Prophylaxis – Reduces frequency in episodic migraine (under‑researched but promising).
- Tinnitus – Improves subjective hearing thresholds in noise‑induced hearing loss.
> Note: Evidence strength varies; strongest for vascular dementia and mild cognitive disorder.
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Contraindications
| Category | Details |
| Absolute Contraindications | Known hypersensitivity to Ginkgo or any formulation component. |
| Bleeding Risk | Increases risk of hemorrhage, especially when combined with anticoagulants (warfarin, aspirin) or NSAIDs. |
| Pregnancy / Lactation | Insufficient safety data; avoid use unless benefit outweighs risk. |
| Co‑administration with CYP3A4 modulators | Potential for altered metabolism – monitor closely. |
| Surgical Procedures | Stop 2–4 weeks prior to elective surgery to reduce peri‑operative bleeding. |
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Dosing
- Standardized Extract (EGb 761)
- Adult: 120–240 mg/day, split 2–3 times.
- Preferred regimen: 24 mg tablets × 5 times/day (≈ 120 mg) or 24 mg tablets × 8 times/day (≈ 192 mg).
- Duration: Minimum 3 months for cognitive outcomes; longer courses (6–12 months) may be required.
- Timing
- Take with food or a full glass of water to reduce GI upset.
- Avoid concurrent intake of high‑fat meals that may slightly delay absorption.
- Special Populations
- Elderly: Similar dosing; consider earlier onset of GI side effects.
- Patients on Anticoagulants: Reduce dose to half; monitor INR or bleeding signs.
- Children: No robust data; generally not recommended.
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Adverse Effects
Common (≤ 10 % incidence)
• Gastrointestinal upset (nausea, diarrhea, epigastric pain)
• Headache, dizziness
• Skin rash or pruritus
Serious (≤ 1 % incidence)
• Bleeding events (epistaxis, menorrhagia, spontaneous hematomas)
• Hypersensitivity reactions (anaphylaxis)
• Severe GI ulceration (rare)
> Advisory: Report any bleeding or severe allergic manifestations promptly.
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Monitoring
| Parameter | Frequency | Rationale |
| CBC & Coagulation (PT/INR) | Baseline, then every 4 weeks if on anticoagulants | Detect occult bleeding or thrombocytopenia. |
| Liver Function Tests (AST, ALT, ALP) | Baseline, then every 3 months | Identify hepatotoxicity. |
| Cognitive Assessments (MMSE / MoCA) | Every 3–6 months | Track therapeutic response and progression. |
| Blood Pressure & Pulse | Every visit | Ginkgo may lower BP; monitor for hypotension. |
| Medication Review | At each visit | Update on possible drug–drug interactions. |
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Clinical Pearls
1. Standardization Matters – Only EGb 761 (or equivalent) contains the proven balance of flavonoids and terpenoids. Non‑standardized supplements can have variable efficacy and safety.
2. Bleeding Vigilance – Even at low doses, Ginkgo can potentiate anticoagulants. Patients on warfarin should undergo INR checks twice a week if Ginkgo is initiated.
3. Timing and Food – Taking Ginkgo with a small snack reduces GI upset; high‑fat meals may blunt peak concentrations but overall exposure remains comparable.
4. Combination Therapy – In vascular dementia, Ginkgo synergizes with donepezil; however, evidence for additive efficacy is mixed. Use at the discretion of the clinician.
5. Pregnancy Check – For women of childbearing potential, a thorough pregnancy test should precede use due to limited safety data.
6. Drug‑Drug Interaction Hot‑Spot – CYP3A4 inducers (e.g., rifampin, carbamazepine) may lower Ginkgo levels; inhibitors (ketoconazole, itraconazole) may increase them, necessitating dose adjustment.
7. Patient Education – Inform patients to report unexplained bruising, nosebleeds, or red‑streak urination; these may signal bleeding complications.
8. Surgical Precaution – Discontinue Ginkgo 2–4 weeks before elective procedures; resumption post‑operative only after hemostasis is assured.
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