Drug Nutrient Interactions

This list provides common drug and nutrient interactions. Please note that the prescription drug listings are not all-inclusive; drugs listed are common examples.

Herb	Drug Class	Type of Interaction
Alfalfa (Medicago sativa) - Leaf	Anticoagulants2,4,9 e.g. Warfarin3	Interact Reduced drug action due to Vitamin K content in alfalfa
	Hormone replacement therapy2,4,9	Interact
	Oral contraceptive2,4,9	Interact
	Xenobiotics3	Increases rate of metabolism

Remedies: Nutritional support, retained water, Cholesterol, menopause, addiction, urinary, bowel problems

Aloe Vera - (A. vera) Latex Powder	All drugs12	Aloe latex will bind all drugs
	Antiarrythmic agents5,11,12 e.g. Quinidine	Interact
	Cardiac glycosides2,3,5,11,12 e.g. Digoxin5	Increases toxicity. Increases effect due to potassium loss, hypokalemia
	Cortico-adrenal steroids5,11	Increases potassium deficiency
	Diuretics3 e.g. Loop diuretics5 e.g. Thiazide diuretics5,11	Increases potassium loss Interact Interact
	Laxative, stimulant20	Increases diarrhea, abdominal pain and fluid loss
	Oral drugs3,11	Decreases absorption of drug due to reduction in bowel transit time
	Glyburide4	Increases hypoglycemic effect
Aloe Vera - Gel or Juice	Glibenclamide3,4	Increases hypoglycemic effect

Remedies: Immune system, Cancer, Heartburn, Arthritis

Anise or Aniseed (Pimpinella anisum) - Seed	Anticoagulants9	Excessive doses of Anise may interact with anticoagulants
	Hormone Replacement Therapy9	Excessive doses of Anise may interact with HRT
	Iron5	Enhances iron absorption across the intestinal mucosa
	Oral contraceptive9	Excessive doses of Anise may interact
	MAOIs9	Excessive doses of Anise may interact with MAOI therapy

Remedies: Digestion, Infection, Respiratory problems and infections, Menopause

Astragalus (Astragalus membranceus) - Root	Acycloir20	Drugs incompatible with herb
	Aldesleukin20	Astragalus with low dose Aldesleukin resulted in a 10-fold potentiation of Aldesleukin's tumor cell killing activity with decreased side effects
	Anticoagulants/Antiplatelet20	Increases risk of bleeding

Remedies: Alzheimer's, Common cold, Sore throat, Chemotherapy support

Basil (Ocimum basilicum) - Leaf	Antidiabetic agents5	May enhance hypoglycemic effects
	Insulin5	May enhance hypoglycemic effects
	Sulfonylureas5	May enhance hypoglycemic effects

Remedies: Digestion, Stomach cramps, Vomiting, Constipation, Anxiety, Headaches

Bay (Laurus nobilis) - Leaf

Insulin5

Herb enhances hypoglycemic actions - may increase insulin's effect more than three fold5

Remedies: Stomach problems, Rheumatism

Bearberry Uva Ursi (Arctostaphylos uva-ursi) - Leaf	Drugs that acidify the urine3,4,5,7 e.g. Vita. C (Absorbic Acid)	May decrease the urinary antimicrobial action
	Drugs known to interact with hydroquinone2	Theoretically, caution should be exercised
	Diuretics5	Enhances electrolyte loss

Remedies: Arthritis, Urinary problems, Diarrhea, Bronchitis, Fever, Hemorrhoids

Bee Pollen

Antidiabetic agents5 Hypoglycemic agents5 Insulin5

Interact - May promote hyperglycemia

Bilberry (Vaccinium myrtillus) - Fruit	Anticoagulants5 e.g. Warfarin4,20	Increases risk of bleeding Increases bleeding time
	ASA4	Interact
Bilberry - Leaves	Insulin3	May cause hypoglycemia

Remedies: Prevent cataracts, Enhance night vision, Blood circulation, Diarrhea, Liver & stomach problems

Birch (Betula) - Leaf

None reported5,10

Remedies: Lessens inflammation, Diuretic, Joint pain, Urinary tract infections

Black Cohosh (Actaea racemosa) - Root	Antihypertensives5	Increases hypotensive effects
	Estrogen7,12	Interact
	Hormone treatments14	Interact
	Tamoxifen4	Augments antiproliferative action (in vitro)

Remedies: PMS, Menstruation problems, Hot flashes

Black Walnut (Juglans nigra) - Bark, leaf hull	Atropine23	Interact
	Codeine23	Decreased absorption

Remedies: Candida, Skin problems

Blue Cohosh (Caulophyllum thalictroides) - Root	Angina therapy4,5,9	Interact
	Antihypertensives5	Decreases effect of drug, increases blood pressure
	Nicotine5	Increases effects of nicotine

Remedies: Muscle spasms, Menstrual disorders, Nervous & memory disorders

Borage (Borago officinalis) - Seed Oil	Epileptogenic drugs20	May manifest seizures (theoretical)
	Phenothiazines9	Interact

Remedies: Skin & nail health

Broom (Cytisus scoparius) - Aerial parts	MAOIs23	Contains tyramine
	Beta blockers5	Potentiates drug
	Antihypertensives5	Interact

Remedies: Diuretic, Emetic, Purgative

Bugleweed (Lycopus ssp) - Aerial parts	Thyroid therapy23	Interact
	Beta blockers5	May mask symptoms

Remedies: Hyperthyroidism, Mood, Overactive heart

Bupleurum (Bupleurum ssp) - Root

Interferon23

May lead to serious lung disease

Remedies: Liver disease, Hemorrhoids, Digestion

Burdock (Arctium lappa) - Fruit & Roots	Oral hypoglycemics2,4,5,9	Increases hypoglycemia
	Insulin3,5	Hypoglycemic effect
- Leaves	Oral hypoglycemics4	Increases hypoglycemia

Remedies: Acne, Psoriasis, Rheumatoid arthritis

Calendula (Calendula officinalis) - Flowers

Hexobarbitol2,3

Extends duration of drug action (rats)

Remedies: Eczema, Gastritis, Sunburn, Minor burns and wounds

Catnip (Nepeta cataria) - Aerial parts

Dextromethorphan23

Potentiates effect of drug

Remedies: Sedation, Colic

Cat's Claw (Uncaria tomentosa) - Rootbark	Anticoagulants5	Potentiates effect of drug
	Antihypertensives5	Potentiates effect of drug
	Oral contraceptives4	May antagonize effect of drug
	Hormone replacement therapy4,7	May antagonize effect of drug
	Immunosuppressives4	May antagonize effect of drug
	Insulins7	Interact
	Ulcer medications10	Interact
	Vaccines7	Interact

Remedies: Stimulates immune system (taken by HIV and cancer patients), Rheumatism, Gastric, Ulcers, Tumors & Dysentery

Cayenne Pepper (Capsicum frutescens) - Fruit	All Drugs2	Increases hepatic metabolism
	Antihypertensives2,5,9	Interact
	ACE Inhibitors3,16	May increase cough
	Centrally acting adrenergic agents5 e.g. Clonidine, Methyldopa5	Decreases effect of drug
	Hexobarbital3	Increases plasma concentration and sleep with acute use and decreases with chronic use (rats)
	MAOI2,5,9	Interact, hypertensive crisis
	Theophylline3,16	Increases absorption and bioavailability of drug

Remedies: Digestion, Blood circulation, Arthritis, Colds, Sore throat, Sinus problems

Chamomile, German (Matricaria recutita) - flowers	All Drugs5	Decreases absorption of drugs secondary to Chamomile Antispasmodic activity in GI tract
	Anticoagulants5,9	Large doses of herb may interact

Remedies: Digestion, Diuretic, Sleep aid, Colitis, Diverticulosis, Fever, Headaches, Stress

Chaparral (Larrea tridentata) - Aerial Parts	Anticoagulants20	Chaparral has been shown to interact with platelet adhesion and aggregation in aspirin-treated patients
	Barbiturates4	Inhibits metabolism
	MAOIs9	Excessive doses of Chaparral may interact with MAOI therapy

Remedies: Diuretic, Laxative

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Chasteberry (Vitex agnus-castus) - Berry	Dopamine-receptor antagonists1,4,13 e.g. Antipsychotics & Metaclopramide14	Decreases therapeutic effect of drug (animal)
	Dopaminergic drugs	Interact
	Hormone therapy4	Interact
	Oral contraceptives3,4	Interact with efficacy of drug

Remedies: Colds, Coughs

Chondroitin sulfate

Anticoagulants5

Potentiates effects of drug

Remedies: Joint health, Arthritis

Cinnamon (Cinnamomum Zeylanicum) - Bark

None reported1,5

Remedies: Diarrhea, Nausea, Blood circulation, Fungal infection, Digestion

Cloves (Syzgium aromaticum) - Buds

Anticoagulants9

Potentiates anticoagulant effects of drug

Remedies: Antiseptic, Anti parasitic, Digestive aid, Dental problems

Coltsfoot (Tussilago farfara) - Leaf	Antihypertensives4,5,9	Interact
	Cardiovascular therapy4,9	Interact

Remedies: Coughs, Respiratory ailments, Diabetes

Comfrey (Symphytum officinale) - Leaf or Root

None reported4,5

Remedies: Wounds and many skin problems

Cranberry (Vaccinium macrocarpon) - Berry

Renally excreted drugs5

May increase elimination of some drugs excreted in the urine.

Remedies: Urinary tract infections

Dandelion (Taraxacum officinale) - Root	Antidiabetic agents5,9	May potentiate effect of drug, promoting hypoglycemia
	Antihypertensives5	Additive or synergistic hypotensive effect
	Lithium3,4	Toxic effect of lithium worsened
- Leaf	Diuretics2,4,5,9	Potentiates the diuretic action of drug (Herb is rich in potassium)

Remedies: Constipation, Indigestion, Water retention, Alcoholism

Devil's Claw (Harpagophytum procumbens) - Root	Cardiac therapy2,9	Interact
	Antiarrhythmic drugs2,4,5	Theoretical possibility of interaction due to herb's protective action against arrhythmia
	Hypo/hypertensive therapy2,9	Interact
	Warfarin16	Increases risk of Purpura

Remedies: Indigestion, Heartburn and Arthritis

Dong Quai (Angelica sinensis) - Root	Anticoagulants2,5,12	Interact
	ASA12	Interact
	Warfarin4,20	Herb may enhance the anticoagulant effect of drug
	HRT - Hormone Therapy22	Interact

Remedies: Breast cysts, Menopause and PMS symptoms

Echinacea (Echinacea species) - Root/Leaf	Cancer treatements4	Herb stimulated immune system
	Econazole nitrate cream3	Recurrence rate of vaginal candida infection decreases when the herb juice is used simultaneously
	Immunosuppressive agents2,4,9 e.g. Corticosteroids & Cyclosporine4	Herb stimulates immune system
	Hepatotoxic drugs12	Increases liver toxicity with other hepatotoxic drugs
	Warfarin4	Increases bleeding time (anecdotal reports)

Remedies: Boost immune system to prevent colds, flu, ear infections, sore throats, mouth ulcers (cankers), gingivitis and yeast infections

Elder (Sambucus nigra) - Berry

None reported1,2,5,10

Remedies: Colds, Herpes simplex, Sore throat, Flu, Inflammation

Evening Primrose Oil (Oenothera biennis) - Seed	Anticoagulants2,14,20	Interact, may reduce platelet aggregation and potentiate drug action
	Beta-blockers2,14	Decreases action of herb
	Corticosteroids2,14	Theoretically interact
	Epileptogenic drugs2,4,9 e.g. Phenothiazines2,5,9,14,19	Increases epileptic attacks
	Lithium carbonate2	Decreases neurotoxicity
	NSAIDs2,14	Theoretically interact
	Vasodilators20	May potentiate effect of drug

Remedies: Arteriosclerosis, Diabetes, Eczema, Fibrocyctic breast disease, PMS, Rheumatoid arthritis

Fenugreek (Trigonella foenumgraecum) - Seed	All Drugs3,5,9,20	Absorption of all drugs may be affected due to mucilaginous fiber content and high viscosity in gut
	Anticoagulants5,9,10	Interact
	Heart medications10	Interact
	Hormonal therapy9,10	Interact
	Hypoglycemic therapy5,9	Interact
	Insulin3,20	Dose may need adjustment due to hypoglycemic activity
	MAOIs9,10	Interact

Remedies: Lowering cholesterol and triglyceride levels, Diabetes, Arteriosclerosis

Feverfew (Tanacetum parthenium) - Leaf	Anticoagulants2,4,12,13 e.g. Warfarin2,4	Potentiates effect of drug
	Aspirin12,13	Increases antithrombotic effect
	Corticosteroids2	Decreases effect of herb
	Imitrex12	Decreases efficacy of drug
	NSAIDs2,12	Decreases effect of herb
	Tylenol12	Decreases efficacy of drug

Remedies: Migraines

Flax (Linum usitatissimum) - Seed	All Drugs1,3,4,5,13,20	Absorption of drug delayed when herb used as a bulk laxative
	Insulin21	Potentiates effect of drug due to delayed absorption of glucose
	Laxatives5	Increase in laxative actions of flax
	NSAIDs4 e.g. Indomethacin4	Increases prevalence of stomach/intestinal ulcers

Remedies: Bone, Nail, Teeth, Skin health

Forskohlii (Coleus forskohlii) - Root

Clonidine23

Potential interaction

Remedies: Allergies, Asthma, Eczema, Irritable bowel syndrome, Menstrual cramps, High blood pressure, Glaucoma

Herb	Drug Class	Type of Interaction
Garlic (Allium sativum) - Bulb	Anticoagulants2,4,5,7,9,19 e.g. Warfarin1,3,11,12,16,19,20	Interact
	Antiplatelet therapy5	Anticoagulant activity of drug enhances (may double clotting time)
	ASA2,9,12	Enhances effects of antiplatelet therapy Potentiates the anti-thrombotic effect of ASA
	Diabetic Therapy2,9 e.g. Insulin3	Dose of drug may need adjusting due to hypoglycemic effects of herb

Remedies: Cardiovascular system, Congestive heart failure, Lowering cholesterol and triglyceride levels

Ginger (Zingiber officinate) - Root	All drugs3	Increases absorption of drug
	Anticoagulants2,4,5,9,11,19,20	Inhibitory effect on thromboxane synthesis
	Cardiac therapy2,9	Interact
	Cyclophosphamide3	Side effect of vomiting prevented by prior administration of acetone extract of ginger or its component 6-gingerol (PO in Suncus/shrew)
	Diabetic therapy2,9	Interact
	Sulfaguanidine3,4	Increases absorption of drug (rats)

Remedies: Anti-nausea, Anti-vomiting, Blood circulation, Indigestion

Ginko (Ginko biloba) - Leaf	Anticoagulants1,2,4,5,12,13,14,19 & Antiplatelet therapy20	Potentiates effect of drug - Monitor coagulation
	e.g. Aspirin3,12,16,20 NSAIDs4 Warfarin16,20 Ticlopidine20	May introduce spontaneous bleeding Interact Potentiates effect of drug
	MAOIs3,20	May potentiate effects of drug
	Papaverine3	Potentiates effect of intracavernosal injection for impotence (in 20% of patients for whom previously ineffective)
	SSRIs20	Gingko may counter the sexual dysfunction that may be experienced with SSRIs
	Thiazide diuretic18	Herb decreases effect of drug, the interaction causes hypertension

Remedies: Alzheimer's disease, Blood circulatory diseases, Depression, Diabetes, Male impotence, Migraine, Multiple sclerosis, Tinnitus

Ginseng North American (Panax quinquefolius) - Root	Anticoagulation therapy3,4,12,16 e.g. Warfarin20	Interact Decreases INR levels
	Antihypertensives4 e.g. Diuretics20	Interact Decreases diuretic action
	Digitalis12	Increases toxicity
	Estrogen Therapy4,9	Interact
	Oral Hypoglycemia therapy4,5	Interact
	Insulin3	Dose adjustment due to hypoglycemic effect
	MAOIs1,3.4.5.9.11.12.20	Interact
	Oral contraceptives12	Interact
	Psychotherapeutic medication4,12/Antipsychotics19 e.g. Phenelzine4,9,16,20	Interact
	Steroids12,19	Interact

Remedies: Flu, Common cold, Sore throat, Chronic fatigue syndrome, Fibromyalgia, Alzheimer's disease, Arteriosclerosis, Chemotherapy support, Male reproductive health, Stress, Diabetes

Ginseng Siberian (Eleuthero coccus senticosus) - Root	Anticoagulants2,4	Interact
	Antipsychotics4,9	Interact (Stimulant activity)
	Barbiturates2,4 e.g. Hexobarbital3,5	Potentiates effects of drug Increases effect of drug due to inhibition of its metabolic breakdown
	Cardiac therapy2,9	Interact
	Diabetes therapy2,4,9	Interact
	Digioxin2,5,16,19	Increases serum digoxin levels
	Estrogen4	Potentiates effect of drug
	Hypertension therapy2,4	Contra-indicated
	Hypotension therapy2,9	Interact
	Insulin3	May need to adjust dose due to hypoglycemic effect
	Monomycin & Kanamycin3	Increases efficacy in treating Shigella dysentry and Proteus enterocolitis probably due to enhancement of t-lymphocyte activity

Remedies: Alzheimer's disease, Attention deficit disorder, Adjunctive chemotherapy, Chronic fatigue syndrome, Common cold, Diabetes, Flu, Fibromyalgia, Stress

Glucosamine Sulfate (2-Amino-2-deoxyglucose)

Diabetic medication15

Causes a decrease in insulin secretion and in insulin sensitivity (in animal studies)

Remedies: Arthritis, Joint pain

Goldenseal (Hydrastis canadensis) - Root	Anticoagulants4,5,9	Potential interaction
	Antihypertensives5 e.g. Beta blockers5 Calcium channel blockers5	Increases effect of drug
	Barbiturates2,4 e.g. Barbitu	Increases sleeping times (rats)
	Cardiovascular medications4 e.g. Digoxin5	Interact Increases effect of drug
	CNS depressants5 e.g. Alcohol, benzodiazepines5	Enhances sedative effects
	Oral Hypoglycemia Therapy22	Herb lowers blood sugar levels

Remedies: Common cold, Chronic ear infections, Urinary tract infections, Crohn's disease

Grapefruit (Citrus paradisi) - Fruit/Juice	All Drugs including: Benzodiazepines3,18 e.g. Midazolam, triazolam, alprazolam18, Buspirone18	Increases bioavailability Inhibits metabolism by cytochrome P450-3A enzymes
	Calcium Antagonists3,18 e.g. Amiodipine, verapamil, nisoldipine, nifedipine, nitrenipine, felodipine, nimodipine, nicardipine
	Cavedilol18
	Cisapride18
	Clomipramine18
	Coumarin3
	Cyclosporin3,18
	Ethinyl estradiol3,18
	HMG CoA reductase inhibitors18 e.g. Atorvastatin, cerivastatin, lovastatin, simvastatin18
	Saquinavir18
	Tacrolimus18
	Terfenadine3

Remedies: Appetite stimulant, Digestion, Diuretic

Grape Seed Extract

None reported5

Remedies: Good nutritional value

Green Tea (Camellia sinensis) - Leaf	All Drugs	Green Tea has similar interactions as occur with caffeine
	Calcium12	Decreases absorption of calcium
	Doxorubicin5	May enhance the antitumor activity of doxorubicin

Remedies: Stimulates immune system, Infections, Gum disease, some cancer risk reduction, Lowers cholesterol level, High blood pressure, High triglyceride levels

Hawthorn (Crataegus laevigata) - Aerial parts	Antihypertensives5	Increases hypotension
	Cardiac glycosides3,5,12,19 e.g. Digitoxin, Digoxin3, Digitalis1,3,4	Potentiates effect of drug (helps lower digoxin levels where toxicity is a concern)
	Cardiac medications7,9 e.g. Nitrates5	Interact Increases hypotension
	CNS depressants5	Addictive effects

Remedies: Angina, Arteriosclerosis, High blood pressure

Hops (Humulus lupulus) - Strobiles	Alcohol2,9,14,20	Potentiates action of alcohol
	CNS depressants5	Increases effect of drug
	Cytochrome P450 metabolized drugs2,5	Yet to be evaluated
	Pentobarbital3	Increases sleeping time (mice)
	Phenothiazine-type antipsychotics5	Combination of herb and drug increases hyperthermia
	Sedative-hypnotics2,9,14,20	Potentiates effect of drug

Remedies: Anxiety, Insomnia

Horse Chestnut (Aesculus hippocastanum) - Seed

Anticoagulants3,5 ASA3,5

Increased risk of bleeding

Remedies: Varicose veins, Hemorrhoids, Blood circulation

Horseradish (Armoracia rusticana) - Root

Thyroid medications9

Interact

Remedies: Coughs, Diuretic, Sinus, Throat and lung problems

Juniper (Juniperus communis) - Berry	Diuretic therapy2,9	Potentiates effect of drug
	Hypoglycemic therapy2,9	Potentiates effect of drug

Remedies: Urinary tract infections, water retention

Kava (Piper methysticum) - Root	Alcohol1,2,3,5,7,12,14	Potentiates action of herb
	Anticoagulants19	Interact
	Antidepressants7,12	Interact
	Antipsychotics7	Interact
	Barbiturates1,2,4,5,7 e.g. Hexobarbital2 e.g. Pentobarbital3,5	Potentiates action of barbiturates Potentiates effect of drug (animals) Potentiates effect of drug
	Benzodiazepines2,3,4,12,14,19/Tranquillizers12 e.g. Alprazolam2,5,20	Potential interaction Potentiates effect of drug
	Centrally acting drugs1,2,4,7,20	Potentiates effect of drug
	CNS depressants3,5	Potentiates effect of drug
	Levadopa3	Decreases efficacy
	Hepato toxic drugs	Potentiates effect of drug

Remedies: Anxiety

Lemon Balm (Melissa officinalis) - Leaf	CNS depressants14	Interact
	Hexobarbital3	Enhances effect of drug
	Pentobarbital2,3,4	Promotes hypnotic action (mice)
	Thyroid medications2,4,14	Interact

Remedies: Herpes simplex, Indigestion, Insomnia, Nerve pain, Hyperthyroidism

Licorice (Glycyrrhiza glabra) - Root	Agents that prolong the QT interval5 e.g. procainamide, quinidine, terfenadine5	May prolong the QT interval
	Antihypertensives4,5,12	Interact
	Aspirin3,20	Deglycyrrhizinated licorice decreases ulcer formation (rats) & gave greater protection from ASA-induced gastric mucosal damage when used with cimetidine (rats)
	Cardiac glycosides2,3,11 e.g. Digitalis1,3,12,20 Digoxin5	Affect potassium levels Iincreases toxicity due to decreases in potassium
	Cardiovascular drugs4	Interact
	Cathartics4 e.g. Stimulant laxatives3	Interact Additive effect - increases potassium loss
	Corticosteroids3,4,5,11,20 e.g. Hydrocortisone2,3,16, Prednisolone2,16	Interact Potentiates effect of drug Inhibit metabolism, increases plasma concentration
	Diuretics3,4,5,11,12,20 e.g. Loop diuretics2,11, Potassium-sparing diuretics2, Potassium-excreting agents or amiloride4, Spironolactone3,4,5,11, Thiazide1,3,11	Affects potassium, potentiates potassium depletion
	Hormonal therapy4,9 e.g. Oral contraceptives16	Interact Hypertension, edema, hypokalemia
	Estrogen & antiestrogen2	Interact
	Insulin2,3,4,9	Increases electrolyte disturbances
	Nitrofurantoin2	Increases bioavailability

Remedies: Asthma, Bronchitis, Canker sores, Eczema, Herpes simplex, Indigestion, Heartburn, Peptic ulcer, Chronic fatigue syndrome

Lobelia (Lobelia inflata) - Aerial parts

Nicotine therapy5 (smoking cessation treatments)

Contra-indicated - Nicotine and Lobelin are chemically similar in structure

Remedies: Coughs, Colds, Asthma, Bronchitis, Flu, cardiovascular, Epilepsy

Herb	Drug Class	Type of Interaction
Ma Huang (Ephedra sinica) - Aerial parts	All Drugs2	Herb has similar interactions to those occurring with Ephedrine
	Anesthetics4	Interact
	Agents that influence urine pH e.g. Antacids3,4 Acetazolamide20	Interact Acetazolamide may cause increased concentration of ephedrine due to alkalinization of the urine
	ASA4	Potentiates effect of drug
	B adrenegic blockers4,5	Interact
	Cardiac glycosides1,4,11,13 e.g. Digitoxin7	Disturb heart rhythm Interact
	Corticosteroids2 e.g. Dexamethasone3	Interact Increases clearance and thereby reduces effect
	Centrally acting medications2,4 e.g. Antidepressants2 Antihypertensives2,4 Clonidine20	Interact Interact Interact Clonidine may augment the pressor response to ephedrine
	Ephedra alkaloids5	Hypertensive crisis
	Ergot alkaloid derivatives11	Interact
	Guanethidine1,2,4,7,11,13,20	Increases sympathomimetic effect
	Halothane1,2,11,13,20	Disturbs heart rhythm
	MAOIs1,2,3,4,7,11,13 e.g. Tranylcypromine, selegiline, phenelzine, moclobamide3, isocarboxazid20	Increases sympathomimetic effect Severe hypertension
	Methyl Xanthines3 e.g. Theophylline2,3,4,5,20	Interact, increases side effect (GI and CNS) of both herb and drug
	Oxytocin1,2,4,11,13	Hypertension
	Phenothiazine5	Hypotension
	Reserpine3,20	Indirect sympathomimetic effects of ephedrine are antagonized
	Secale alkaloid derivatives1,2	Hypertension
	Sodium Bicarbonate20	Ephedrine toxicity increases due to decreased elimination
	Stimulants2	Interact
	Sympathomimetic agents4,20	Interact

Remedies: Breathing problems, Asthma, Nasal congestion

Marshmallow (Althaea officinalis) - Root	All Drugs1,3,4,5,10	Delays absorption of drug
	Dexamethasone4	Potentiates effect of drug
	Hypoglycemic therapy9,10	Interact
	Insulin5	Increases hypoglycemic effects
	Sulfonylureas5	Increases hypoglycemic effects

Remedies: Peptic ulcer, Chron's disease, Diarrhea, Asthma, Common cold, Sore throat

Meadowsweet (Filipendula ulmaria) - Leaf/Flower

All Drugs2,9 e.g. Anticoagulants2

Herb has similar interactions to those occurring with salicylates Interact

Remedies: Diarrhea, Stomach problems

Milk Thistle (Silybum marianum) - Seed	All Drugs2	Increases live metabolism of all drugs
	Acetaminophen4,19	Reduces hepatotoxicity
	ASA3,4	Altered metabolism in people with liver cirrhosis might be improved
	Butyrophenones20	Reduces lipid peroxidation
	Carbon tetrachloride4,19	Reduces hepatotoxicity
	Cisplatin3,4	Reduces hepatotoxicity
	Cyclosporine4	Reduces hepatotoxicity Synergistic antiproliferative effect on human ovarian and breast cancer cell lines
	Doxorubicin4	Synergistic antiproliferative effect on human ovarian/breast cancer cell lines
	Ethanol4,19	Reduces hepatotoxicity
	Iron4	Reduces hepatotoxicity
	Phenothiazines4,20	Reduces hepatotoxicity
	Phenytoin21	Reduces hepatotoxicity

Remedies: Gallstones, Psoriasis, Liver health

Mistletoe (Viscum album) - Aerial parts	Anticoagulant therapies9	Interact
	Antihypertensives4,5,10	Increases hypotensive effects/check blood pressure regularly
	Antidepressants9,10	Interact
	Cardiac drug5,9,10	Increases cardiac depression
	Coagulant therapies9	Interact
	CNS depressants5	Increases sedative effects
	Hypotensive therapies9	Interact
	Immunosuppressants5,9	Cytotoxic and immunostimulant effects
	MAOIs4	Interact/monitor

Remedies: Blood pressure and heart, Mood, Migraine

Nettle (Urtica dioica) - Leaf	Anticoagulants4/ Coagulant therapy4	Interact
	Antihypertensives2,4,9	Interact
	CNS depressants4,9	Potentiates effect of drug
	Diabetic medication2,4,9	Interact
	Diclofenac (low dose)3,4	Leaf extract enhances anti-inflammatory effect of diclofenac Potentiates effect of drug
	Diuretics2,5	Potentiates effect of drug
	Hypotension medication4,9	Interact
- Root	Protatic Hyperplasia Therapy22 e.g. Tamsulosin	Potentiates effect of drug

Remedies: BPH (enlarged prostate), hay fever

Passionflower (Passiflora incarnata) - Leaf	Barbiturates4 e.g. Hexabarbital, Pentabarbital2,3	Increases hypnotic action Increases sleeping time (animal)
	Centrally Acting Medications2,4,5	Increases hypnotic action and potential for monoamine oxidase inhibition
	CNS depressants20	Potential for additive effects and increases sedation
	MAOI Antidepressants5,7,9	Interact

Remedies: Anxiety, Insomnia

Pau D'arco (Tabebuia impetiginosa) - Bark	Anticoagulants5,20	May potentiate effects of drug, prolongation of prothrombin time20
	Iron5	Decreases absorption of iron

Remedies: Infections and yeast infections

Peppermint (Mentha x piperita) - Leaf

Ulcer treatment e.g. H2 Receptor Blockers

May antagonize achlohydria

Remedies: Migraine, Nerves, Stomach disorder, Heartburn, Herpes, Abdominal cramps

Pine Bark Extract (Pinus maritima)

None reported4,5

Remedies: Chronic venous insufficiency

Propolis - Resin

Tetracycline24

Increases effectiveness

Remedies: Anemia, Skin healing, Respiratory problems, Immune system support, Digestion

Psyllium (Plantago psyllium) - Seed	All drugs1,3	May delay absorption of drugs
	Anti-coagulants21	Delays absorption of drug
	Anti-convulsants e.g. Carbamazepine5,20	Decreases absorption and concentration of drug
	Cardioactive drug5 e.g. Beta blockers, calcium channel blockers, digitalis5	A possibility that the herb enhances digitalis effect of the drug (highly speculative)
	Insulin3	Drug dosage must be adjusted due to slowing of dietary carbohydrate absorption
	Lithium3,5,16	Decreases concentration due to reduction of drug absorption

Remedies: Constipation, Diarrhea, Hemorrhoids, Irritable bowel syndrome, Obesity, Arteriosclerosis, High cholesterol, High triglyceride level, Psoriasis

Puncture Vine (Tribulus terrestris)

None reported4

Remedies: Vitiligo (whitening of skin), Impotence, Female infertility, Urinary problems

Pygeum (Prunus africana) - Bark

Antibiotics for prostate and bladder infections4

Enhances effectiveness of drug

Remedies: Urinary problems, Enlarged prostate

Red Clover (Trifolium pratense) - Blossoms	Anticoagulants5,9,10 e.g. Heparin, Warfarin5	May increase risk of bleeding
	Antiplatelet agents5 e.g. ASA, clopidogrel, ticlopidine5	May increase risk of bleeding
	Hormone Replacement Therapy9,10	Interact
	Oral Contraceptive5,9,10	May enhance action of drug by increasing estrogen components

Remedies: Coughs Eczema, Possible cancer reduction

Red Raspberry (Rubus idaeus) - Leaf

Antidiabetic agents5,9

Increases effectiveness of hypoglycemic action

Remedies: Menstrual problems, Diarrhea, Canker sores

Red Yeast Rice

lovastatin23 Simvastatin23 Atorvastatin23

Additive effect similar in (Cholestin)

Remedies: Lowering cholesterol levels

Rosehips (Rosa canina)

None reported5

Remedies: Colds, Infection

Rosemary (Rosmarius officinalis) - Leaf

Disulfiram5

Disulfiram reaction if herbal product contains alcohol

Remedies: Circulatory system, Heart problems, High blood pressure, Menstruation

Royal Jelly

Antidiabetic agents5

May lead to loss of glycemic control in diabetic patients

Remedies: Appetite stimulant, Chronic fatigue syndrome, Liver disease, Insomnia, Multiple sclerosis

Herb	Drug Class	Type of Interaction
Sage (Salvia officinalis) - Leaf	Anticonvulsants5,9	Lowers seizure threshold
	Antidiabetic agents5,9 e.g. Insulin5	Antagonizes glycemic control
	Sedatives9	Herb may potentiate sedative effects of other drugs

Remedies: Menopause, Tonsillitis, Fever

Saw Palmetto (Serenoa repens) - Berry	Hormone replacement therapy2,4,9	Interacts because of its anti-androgen and estrogenic activity
	Oral contraceptives2,4,9	Interacts because of its anti-androgen and estrogenic activity

Remedies: BPH (enlarged prostate)

Schisandra (S. chinensis) - Berry

Acetaminophen23

Reduces hepatotoxicity

Remedies: Coughs, Asthma, Urinary problems, Tonic

Scullcap (Scutellaria laterifolia) - Aerial parts	Centrally-acting medications2	Potentiates effect of drug
	Sedatives and tranquillizers3,4	Interact

Remedies: Infertility, Nerve disorders

Scullcap, Chinese (Scutellaria baicalensis) - Root	Immunosuppressives5	Possible interaction
	Platelet aggregation inhibitors3,4	Potentiates effect of drug

Senna (Cassia ssp) - Leaf, Pod	Indomethacin5	Decreases drug levels
	Calcium channel blockers5	Potentiates potassium depletion
	Digoxin23	Interacts

Remedies: Sore throat, Fevers, Heart problems

Slippery Elm (Ulmus rubra) - Aerial parts

All Drugs7

May interfere with the absorption of drugs taken simultaneously

Remedies: Gastritis, Chron's disease, Cough, Common cold, Sore throat

St. John's Wort (Hypericum perforatum) - Aerial parts	All Drugs21,22	Drugs metabolized by cytochrome P450 3A4 enzyme system have potential to interact
	Antabase12	Interact
	Anitdepressants4,5,12,17 e.g. Trazadone nefazodone16,17 see MAOIs & SSRIs below	Serotonin syndrome
	Anti-epilepsy drugs17 e.g. Phenytoin carbamazepine phenobarbital17	Interact
	Anti-retroviral drugs e.g. Indinavir	Interact
	Atypical antipsychotics12 e.g. Olanzapine, risperidone12	Interact
	Beta2 agonists12	Interact
	Dextromethorphan2,12	Interact
	Dibenzazepine Derivatives2 e.g. Amitriptyline, doxepin, carbamazepine2	Interact
	Digoxin5,16,17	Interact
	Dopamine agonists12	Interact
	Immunosuppressants17 e.g. Cyclosporine16,17,20	Interact - Decreases cyclosporine plasma concentration20
	Meperidine2	Interact
	Metronidazole12 Midodrine20	Interact Enhances pressor effect
	Migraine therapies17	Interact
	Monoamine Oxidase Inhibitors (MAOIs)2,3,5,9,12,20 e.g. Phenelzine, tranylcypromine, isocarboxazid	Interact
	Narcotics5 e.g. Morphine2	Interact
	Oral Contraceptives16,17	Interact - can make ineffective
	Reserpine3	Decreases effect of drug (mice)
	Selective Serotinin Reuptake Inhibitors (SSRIs)2,3,4,5,7,12,16,17,20 e.g. Fluoxetine, paroxetine5, sertraline	Serotonin syndrome
	Sympathomimetics2,5,12 e.g. Ephedrine, methyldopa, dopamine, trytophan	Interact
	Theophylline4,12,16,17,20	Interact
	Tyramine containing foods2,5	Decreases theophylline level Interact (speculative)
	Warfarin17	Interact

Remedies: Depression, Vitiligo (whitening of skin), Recurrent ear infections

Tea Tree Oil (Melaleuca alternifolia) - Leaf

None reported2,4,5,12

Remedies: Yeast infection, Vaginitis, Athletes foot, Acne

Thyme (Thymus vulgaris) - Leaf & Flower

None reported1,2,5

Remedies: Digestion, Fever, Headache, High cholesterol, Skin problems

Turkey Tail (Coriolus versicolor)

Cyclophosamide23

Cyclophosamide23

Remedies: Respiratory problems, Mood, Tonic

Tumeric (Curcuma longa) - Root	Anticoagulants5	Additive effects on platelets
	Immunosuppressants5	Decreases effects of drug
	NSAIDs5	Inhibits platelet function and increases risk of bleeding
	Reserpine and indomethacin3	Tumeric root solid alcoholic extract reduces the frequency of gastric and duodenal ulcer (rats)

Remedies: Bursitis, Rheumatoid arthritis, Liver health, Arteriosclerosis

Uva Ursi see Bearberry

Remedies: Urinary tract infection

Valerian (Valeriana officinalis) - Root	Alcohol5,11,16	Potentiates effects of alcohol
	Anticonvulsants12	Increases seizures
	Barbiturates19 e.g. Pentobarbital, thiobarbital3	Increases sleeping time
	Benzodiazepines3,19 e.g. Diazepam3	May be helpful in withdrawal from benzodiazepines
	CNS depressants2,5,14,19	Potentiates effects of drug
	Sedative medications4,9,11,12,14	Potentiates effects of drug

Remedies: Insomnia

Wild Yam (Dioscorea vilosa) - Root

Oral Contraceptive22

Interact - may interfere with effectiveness of contraceptive

Remedies: High cholesterol, High triglyceride levels, Abdominal cramps, Menopause, Muscle pain and spasms

Willow (Salix) - Bark	All Drugs1,2,9	Willow has similar interaction to those occurring with salicylates. Irreversible inhibition of platelet aggregation by aspirin cannot be induced by structurally different salicin21
	Anticoagulants5,9	Increases bleeding
	Antihypertensives5	Reduces effect
	Diuretics5	Increases risk of salicylate toxicity (highly speculative)
	Methotrexate9	Interact
	Metoclopramide9	Interact
	NSAIDs5,13	Interact
	Phenytoin9	Interact
	Probenecid9	Interact
	Salicylates9,13	Interact (no cases reported)
	Spironolactone9	Interact
	Valproate9	Interact

Remedies: Headache, Pain, Backache, Nerve pain, Toothache

Yarrow (Achillea millefolium) - Aerial parts	Antacids4	Interact
	Anticoagulant therapy4,5,9	Interact
	CNS depressants5	Increases sedation
	Diuretics4	Interact
	H2receptor antagonists4	Interact
	Hypertensive4,5,9 / Hypotensive therapy4,9	Interact
	Sedatives4	Interact

Remedies: Inflammation, Improves blood clotting, Diuretic, Fever, Some inflammatory disorders

Yohimbe (Pausinystalia yohimbe) - Bark	a-adrenoceptor blocking agents3 e.g. Phenoxybenazamine, phentolamine3	Increases toxicity of yohimbine
	Amobarbital3	Interact
	Antidepressants5,7,20	Interact
	Atropine3	Interact
	Beta blockers3 e.g. Propranolol, penbutolol, metrprolol3	Protects against yohimbine toxicity (mice)
	Central a2-adrenergic agonists3 e.g. Guanabenz, a-methylnorepinephrine3	Reverses hypotensive effects
	Clonidine3	Reverses hypotensive effects
	Hypotensive drugs1,20	Potentiates
	MAOIs1,3,20	Potentiates
	Naloxone3,20	Affects synergistically enhances
	Phenothiazines3 e.g. Chlorpromazine, promazine3	Increases toxicity of yohimbine
	Reserpine3	Interact
	Sedatives3	Increases effect of drug
	SSRIs5	Increases stimulation
	Sympathomimetics3,5,10 e.g. Epinephrine, ephedrine, amphetamine, cocaine3	Increases toxicity of yohimbine
	Thiozanthenes3 e.g. Chlorprotixene3	Increases toxicity of yohimbine
	Tricyclic anti-depressants3,5,16 e.g. Clomipramine3,20, imipramine, amitriptyline3	Combination of herb and drug may cause hypertension Lower doses of yohimbine may have favorable effect in orthostatic hypotension induced by tricyclic anti-depressants
	Tyramine containing foods5,20	Increases blood pressure

Remedies: Depression, Male impotence

References

1. Blumenthal, Mark, Goldberg, Alicia, & Brinckmann, Josef. (2000). Herbal medicine: Expanded commission E monographs. Newton, MA: Integrative Medicine communications.


2. Boon, Heather, & Smith, Michael. (1999). The botanical pharmacy: The pharmacology of 47 common herbs. Kingston, ON: Quarry Press Inc.


3. Brinker, Francis. (1998). Herb contraindications and drug interactions: With appendices addressing specific conditions and medicines (2nd ed.). Sandy, OR: Eclectic Medical Publications.


4. Chandler, Frank. (Ed.). (2000). Herbs: Everyday reference for health professional. Ottawa, ON: Canadian Pharmacists Association and the Canadian Medical Association.


5. Fetrow, Charles W., & Avila, Juan R. (1999). Professional's handbook of complementary and alternative medicines. Springhouse, PA: Springhouse Corp.


6. Karch, Steven B. (1999). The consumer's guide to herbal medicine. New York: Advanced Research Press Inc.


7. Lininger, Schuyler W. Jr., Gaby, Alan R., Austin, Steve, Brown, Donald J., Wright, Johathan V., & Duncan, Alice. (1999). The natural pharmacy (2nd ed.). Rocklin, CA: Prima Publishing.


8. [Interactions not included in manual due to time constraints] Miller, Lucinda G., & Murray, Wallace J. (Eds.). (1998). Herbal medicinals: A clinician's guide. New York: Pharmaceutical Products Press.


9. Newall, Carol A., Anderson, Linda A., & Phillipson, J. David. (1996). Herbal medicines: A guide for health-care professionals. London: Pharmaceutical Press.


10. Peirce, Andrea. (1999). The American pharmaceutical association practical guide to natural medicines. New York: William Morrow and Company Inc.


11. World Health Organization. (1999). WHO monographs on selected medicinal plants - Volume 1. Geneva.


12. Kuhn, Merrily A. (1999). Complementary therapies for health care providers. Baltimore, MD: Lippincott Williams and Wilkins.


13. Gruenwald, Joerg, Brendler, Thomas, & Jaenicke, Christof. (Eds.) (1998). PDR for herbal medicines (1st ed.). Montvale, New Jersey: Medical Economics Company.


14. Wong, Albert H.C., Smith, Michael, & Boon, Heather. (1998). herbal remedies in psychiatric practices. Archives of General Psychiatry 55, 1033-1044.


15. Bedard, Mario. (2000). Glucosamine. CPJ 133, 5, 22-23.


16. Fugh-Berman, Adriane. (2000). Herb-drug interactions. The Lancet 355, 9198, 134-138.


17. Health Canada. (April 7, 2000). Advisory letter to healthy care professionals.


18. Canadian Pharmacists Association. (2000). CPS (35th ed.). Ottawa.


19. Nemecz, George, & Combest, Wendell L. (2000). Herbal Remedies. In Loyd V. Allen Jr., Rosemary R. Berardi, Edward M. DeSimone II, Janet P. Engle, Nicholas G. Popovich, Wendy Munrow Rosenthal, & Karen J. Tietze (Eds.), Handbook of Non-Prescription Drugs (2nd ed., pp. 953-982). Washington: American Pharmaceutical Association.


20. AltMedDex System: Complementary and Alternative Monographs. [Electronic database]. (2000). Micromedex, Inc.


21. Blumenthal, M Herbalgram 49, 2000.


22. Rogers, Robert, Evidence Gathered in Clinical Practice.


23. Meletis, Chris (2001) Instant Guide to Drug Herb Interactions, New York, Dorling Kindersley Publishing.


24. W. Krol et al, Journal of Ethnolpharmacology 1996. Vol. 55.