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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,
Oral contraceptives 1,3

 

 

Antihyperlipidemics 1

Herb affects hypothalamus-pituitary system, decreases luteinizing hormone secretion and binds estrogen receptors
May decrease response to estrogen



Possible additive effect

Borage
(Borago officinalis)
Anti-inflammatory, sedative

Anticoagulants,
Antiplatelet agents 2

Anxiolytics 2

May prolong bleeding time



Additive sedation

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


Estrogens 1

Herb contains coumarin constituents; Possible additive drug effect


Herb contains phytoestrogens; May result in estrogen excess

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


NSAIDs, Corticosteroids,
B-blockers,
Anticoagulants 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
Cola, Kola
(Cola nitida)

 

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,
Ma Huang, pseudoephedrine, yohimbine 3,4

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,
St. John's Wort 3

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