🌿 Folk Prescriptions

In recent years, reports on adverse effects of herbal medicines abroad have increased continuously. Besides well-known cases involving Radix Stephaniae Tetrandrae (Guang Fang Ji), Caulis Sinomenii (Guan Mu Tong), and Aristolochia species causing renal impairment, foreign pharmacologists have also investigated whether common plant-based remedies (including herbal medicines) interact adversely when combined with synthetic drugs. Results revealed that synthetic drugs and herbal remedies do interact, potentially increasing or decreasing the efficacy or toxicity of one or both drugs.
Below are some adverse interactions identified by Dr. Adeline, MD from the University of Washington, based on authoritative medical literature (1994–1999):
▲ Ginkgo biloba, garlic, Angelica sinensis, and Salvia miltiorrhiza used with warfarin (anticoagulant) may increase bleeding tendency.
▲ Ginkgo biloba used with acetaminophen (paracetamol) or ergotamine may lead to bilateral epidural hematoma (cases reported even with ginkgo alone).
▲ Ginkgo biloba used with thiazide diuretics may cause hypertension.
▲ Ginkgo biloba used with aspirin may result in anterior chamber hemorrhage, as ginkgo flavonoids are strong inhibitors of platelet-activating factor (PAF).
▲ St. John’s Wort (Hypericum perforatum) used with serotonin reuptake inhibitors (e.g., trazodone, sertraline, nefazodone) may induce mild serotonin syndrome.
▲ St. John’s Wort used with theophylline, cyclosporine, digoxin, or phenprocoumon may reduce their bioavailability.
▲ St. John’s Wort used with paroxetine (an antidepressant) may cause somnolence and incoherent speech.
▲ St. John’s Wort used with oral contraceptives (e.g., ethinylestradiol, desogestrel) may lead to genital ulceration and bleeding.
▲ St. John’s Wort used with HIV protease inhibitor indinavir may drastically reduce indinavir concentration, rendering it ineffective and potentially promoting HIV drug resistance.
▲ Ginseng used with antidepressants (e.g., phenelzine) may cause headache, tremors, and mania.
▲ Areca nut used with antipsychotics (e.g., flupentixol, cyproheptadine, fluphenazine) may worsen extrapyramidal symptoms.
▲ Areca nut used with prednisolone or salbutamol may fail to control asthma, as arecoline induces bronchial constriction in a dose-dependent manner.
▲ Herbals containing anthraquinones (e.g., Cassia acutifolia, Rhamnus frangula) and soluble fiber (e.g., Plantago ovata) may reduce absorption of certain synthetic drugs such as metformin, glipizide, and penicillin derivatives.
Dr. Adeline believes that adverse interactions between herbal remedies and synthetic drugs go far beyond these examples. As awareness and research grow, more discoveries are expected. She emphasizes that clinicians should inquire about patients’ herbal use and clearly inform them of known risks. For instance, patients with coagulopathy, those awaiting surgery, or those undergoing anticoagulant therapy should avoid Ginkgo biloba, Salvia miltiorrhiza, Angelica sinensis, papaya, and garlic, as these herbs may render anticoagulants ineffective and increase bleeding risk.