Selected Herb-Drug Interactions
| HERB | COMMON INDICATION | DRUG | POTENTIAL EFFECT |
| Alfalfa (Medicago sativa) |
Multiple, including treatment of arthritis, asthma, dyspepsia, hyperlipidemia, and diabetes | Anticoagulants 1,2 | Contains coumarin constituents and vitamin K; excessive use can interfere with drug therapy |
| Aloe vera latex | Strong cathartic | Cardiac glycosides, Thiazide diuretics 3 | Can cause electrolyte imbalance and hypokalemia; May potentiate drug toxicity |
| Angelica (Angelica archangelica) | Loss of appetite, peptic discomfort | Anticoagulants 2 | Contains coumarin constituents; may potentiate drug effect |
| Bearberry Uva-Ursi (Arctostaphylos uva-ursi) |
Urinary tract antibacterial, astringent, diuretic | Urinary acidifiers, Cranberry Juice 2 Diuretics 4 NSAIDs 4 |
Inactivated by urinary acidifiers; active compound released only in alkaline urine. Decreased drug effect Increased gastrointestinal irritation |
| Black cohosh Baneberry, bugwort, Squawroot, Rattleroot (Cimicifuga racemosa) | Hot flashes, premenstrual discomfort and dysmenorrhea | Estrogens,
Antihyperlipidemics 1 |
Herb affects hypothalamus-pituitary system, decreases luteinizing hormone secretion and binds estrogen receptors |
| Borage (Borago officinalis) |
Anti-inflammatory, sedative | Anticoagulants, Anxiolytics 2 |
May prolong bleeding time |
| Bromelain (Ananas comosus) | Acute post-operative and post-traumatic swelling | Antiplatelet agents 2,5 | Increased risk of bleeding |
| Capsicum (Capsicum frutescens, C. annum) | Shingles, trigeminal and diabetic neuralgia | Monoamine oxidase inhibitors 6 Antiplatelet agents 2 |
Herb increases secretion of catecholamines, increases risk of hypertensive crisis Increased fibrinolytic activity, may prolong bleeding time |
| Cascara Bitter bark (Rhanmus purshiana, Cascara sagrada) |
Stimulant laxative | Cardiac glycosides, Thiazide diuretics 3 |
Can cause electrolyte imbalance and hypokalemia; May potentiate drug toxicity |
| Chamomile (Matricaria recutita) | Mild sedative, antispasmodic and antiseptic agent | Iron 4 Anticoagulants 1,4 |
Tannin content in herb may inhibit iron absorption Herb contains coumarin constituents; May interfere with drug effects |
| Chaste tree berry (Vitex agnus-castus) | Menstrual disorders | Dopamine receptor antagonists (i.e., phenothiazines) 3 | Herb has dopaminergic effect, may antagonize drug effect |
| Dong Quai (Angelica polymorpha, A.dahurica, A.atropurpurea) |
Menstrual disorders | Anticoagulants, Antiplatelet agents 2
|
Herb contains coumarin constituents; Possible additive drug effect
|
| Echinacea (Echinacea augustifolia, E.pallida) | Cold, flu | Immunosuppressants 3,7
Arniodarone, Anabolic steroids, Ketoconazole, Methotrexate 4 |
Short-term use: phagocyte production stimulated, counteracts drug effect; Chronic use (>6-8 wk): immunosuppressive, enhances drug effect. Increased risk of hepatotoxicity |
| Evening primrose (Oenothera biennis) | Lower serum cholesterol, atopic eczema | Phenothiazines, anticonvulsants, 4,6
|
Increased risk of seizures in patients taking drug known to lower seizure threshold
|
| Feverfew (Tanacetum parthenium) | Migraine, fever, menstrual problems | Anticoagulants Antiplatelet agents 2,4 NSAIDs 4 Iron 4 |
Additive anticoagulant, antiplatelet effects; Increased risk of bleeding Decreased herbal effect Tannin content in herb may inhibit Iron absorption |
| Garlic (Allium sativum) | Hyperlipidemia | Anticoagulants Antiplatelet agents 2,4 Hypoglycemic drugs 3.8 |
Inhibits platelet aggregation; Additive anticoagulant, antiplatelet effects May potentiate drug effect |
| Ginkgo (Ginkgo biloba) | Varicose veins, intermittent claudication, dementia, vertigo, tinnitus, SSRI- induced sexual dysfunction, cerebral vascular insufficiency | Anticoagulants Antiplatelet agents 3,4 Anticonvulsants 4 Tricyclic antidepressants, other drugs that decrease seizure threshold 4 |
Inhibits platelet aggregation, may have additive anticoagulant, antiplatelet effects May increase risk of seizures, decrease drug effect Increased risk of seizure |
| Ginseng Asian ginseng (Panax ginseng, P.quinquefolium) |
Normalize the body, and provide resistance to stress | Hypoglycemic drugs 7.9 Furosemide 3 Digoxin 8 Monoamine oxidase inhibitors 4,9 Anticoagulants, antiplatelet agents 2,4 Estrogens, corticosteroids 4,9 Drugs that cause gynecomastia 3,10 (e.g., calcium channel blockers, cardiac glycosides, methyldopa, phenothiazines, spironolactone) |
Herb has hypoglycemic effect Decreased diuretic effect May increase serum digoxin concentrations Headache, visual hallucination, tremor, manic episodes Decreased effectiveness of warfarin Additive drug effects Herb contains estrone, estradiol, estriol; Has additive estrogenic effects |
| Goldenseal (Hydrastis canadensis) | Mucosal inflammation, gastritis | Anticoagulants 2,8 | Contains berberine; inhibits anticoagulant effects |
| Gossypol | Male contraceptive | Diuretics 4 NSAIDs 4 |
Potentiate hypokalemia Increased gastrointestinal irritation |
| Guarana (Paullinia cupana) |
CNS stimulant, potentiate analgesics | Anticoagulants 3 | Inhibits platelet aggregation, increases risk of bleeding |
| Hawthorn (Crataegus laevigata, C.monogyna, C.pinnatifida) | Heart disease, sleep disorders angina, | Antihypertensives 3 Digoxin 4 |
High dose of herb causes hypotension Potentiates drug effect |
| Hops (Humulus Lupulus L) |
Insomnia | Anxiolytics, alcohol 3,6 | Potential additive sedation |
| Horse chestnut (Aesculus hippocastanum) | Varicose veins, other venous insufficiencies | Anticoagulants 2,3 | Herb contains coumarin-like constituent; May increase risk of bleeding |
| Karela Bitter melon |
Diabetes mellitus | Hypoglycemic drugs 4 | Potentiates drug effect |
| Kava-Kava (Piper methylsticum) | Sleep disorders, anxiety | Alcohol, Benzodiazepines, CNS depressants 3,4,6 |
Additive sedative effects |
| Kelp (Laminaria hyperborea) |
Thyroid dysfunction | Thyroid hormones 4,7 | Herb contains iodine, may interfere with thyroid replacement |
Kolanut
|
Use in beverages for caffeine content | Theophylline, guarana caffeine 3,10 |
Herb contains caffeine, potential additive CNS stimulation |
| Lemon balm (Melissa officinalis L) | Insomnia, anxiety | CNS depressants 6 Thyroid hormones 6 |
Potentiates CNS depression May bind thyrotropin and interferes with therapy |
| Licorice (Glycyrrhiza glabra) | Expectorant, peptic ulcers | Spironolactone 4,7 Cardiac glycosides, Thiazide diuretics 3,4 Corticosteroids, Cyclosporine 4 Monoamine oxidase inhibitors 1 |
Antagonism of diuretic effect Can cause hypokalemia; May potentiate digoxin toxicity Herb has immunostimulating effect; May decrease response to the drugs Herb contains sympathomimetic amines, increased risk of hypertensive crisis |
| Ma Huang Ephedra, squaw tea, mormon tea, popotillo, sea grape (Ephedra species) | Asthma, weight loss | Oxytocin, Methyldopa, B-blockers, Caffeine, Monoamine oxidase inhibitors, Theophylline, Sympathomimetics, St.John's wort, Guanethidine, Cardiac glycosides 3,10 | Increased sympathomimetic action; may induce hypertension, CNS stimulation |
| Passionflower (Passiflora incarnata) | Anxiety, restlessness | Anticoagulants 2 | Excessive dose may increase risk of bleeding |
| Pau D'Arco Taheebo, Trumpet bush (Lapacho colorado) | Antineoplastic | Anticoagulants 2,3 | May potentiate drug effects |
| Psyllium Plantago, plantain (Plantago species) |
Bulk-forming laxative, Irritable bowel syndrome, Cholesterol lowering | Lithium, digoxin 3, 10 Antihyperlipidemics 1 Anticoagulants 2 |
Decreased intestinal drug absorption Possible additive effects Herb contains vitamin K; May interfere with anticoagulant therapy |
| Red clover (Trifolium pratense) | Anticoagulants 1,2 | Herb contains coumarin; large amount may increase risk of bleeding | |
| Sarsaparilla | Diuretic | Digitalis, bismuth 3 | Increased absorption of digitalis and bismuth |
| Honduras (Smilax species) |
Drugs metabolized by CYP450 enzymes 3,10 | Induces CYP450 enzymes; increases drug elimination | |
| Saw palmetto Sabal, Cabbage palm (Serenoa repens) |
Benign prostatic hyperplasia | Iron 7 Estrogens 4 |
Tannin content of herb may limit iron absorption 7 _______________________ Potential additive effects |
| Senna (Cassia acutifolia, C.augustifolia, Senna alexadrina) | Constipation | Digitalis, Diuretics 3,10 | Chronic use may cause hypokalemia and potentiate drug toxicity |
| Shankapulshpi (Ayurvedic preparation) | Phenytoin 1,4 | Reduced drug concentrations and half-life; Decreased drug effect | |
| Siberian ginseng (Eleutherococcus, senticosus) | Improve endurance | Digitalis 4 | May interfere with drug level assay |
| St.John's wort (Hypericum perforatum) | Depression | Antidepressants, sympathomimetic amines, Digoxin 11 Iron 4 Piroxicam, Other photosensitizers 3,4 |
Herb may have monoamine oxidase inhibitor or selective serotonin reuptake inhibitor effects; Possible hypertensive crisis, serotonin syndromes Hypericum extract may reduce peak and trough digoxin concentrations Tannin content of herb may limit iron absorption Increased risk of photosensitivity, avoid use with UV light therapy |
| Turmeric Tumeric, indian saffron (Curcuma longa) |
Dyspepsia | Antiplatelet agents 2 | Herb contains curcumin; may potentiate antiplatelet activity |
| Uzara root (Uzarae radix) |
Diarrhea | Digoxin 4,7 | Additive digoxin-like cardiac effects |
| Valerian (Valeriana officinalis) |
Anxiolytics | Opiates, Alcohol, Barbiturates, CNS depressants 3,4 |
Additive sedation |
| Wormwood | Loss of appetite, dyspepsia | Anticonvulsants 4 | May lower seizure threshold |
| Yohimbe Yohimbine (Pausinystalia yohimbe) |
Impotence | Antihypertensives, Caffeine, Ephedrine, Ma Huang 3,10 Antidepressants, |
Herb has a2-antagonist activity My induce hypotension or hypertension, tachycardia. May have monoamine oxidase inhibitor activity |
NSAID = Nonsteroidal anti-inflammatory drug
Published by the University of Michigan Health System Drug Information Service
