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 Antiarrhythmic 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 membranaceus) – Root Acyclovir20 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 spp) – Aerial parts Thyroid therapy23 Interact Beta blockers5 May mask symptoms Remedies: Hyperthyroidism, Mood, Overactive heart Bupleurum (Bupleurum spp) – 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 Hexobarbital2,3 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) – Root Bark 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 w Chasteberry (Vitex agnus-castus) – Berry Dopamine-receptor antagonists1,4,13
e.g. Antipsychotics & Metoclopramide14 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 treatments4 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, Fibrocystic 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 officinale) – 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 Ginkgo (Ginkgo 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
Ginkgo 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 Digoxin2,5,16,19 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 dysentery 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. Amlodipine, verapamil, nisoldipine, nifedipine, nitrendipine, felodipine, nimodipine, nicardipine Carvedilol18 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 Levodopa3 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
Increases 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 adrenergic 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, moclobemide3, 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, Crohn’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 the inflammatory response effect of diclofenac
Potentiates effect of drug Diuretics2,5 Potentiates effect of drug Hypotension medication4,9 Interact – Root Prostatic Hyperplasia Therapy22
e.g. Tamsulosin Potentiates effect of drug Remedies: BPH (enlarged prostate), hay fever Passionflower (Passiflora incarnata) – Leaf Barbiturates4
e.g. Hexobarbital, Pentobarbital2,3 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 achlorhydria 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 Rose Hips (Rosa canina) None reported5 Remedies: Colds, Infection Rosemary (Rosmarinus 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 lateriflora) – 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 spp) – 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, Crohn’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 Antabuse12 Interact Antidepressants4,5,12,17
e.g. Trazodone
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 Serotonin 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, tryptophan 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) Cyclophosphamide23 Cyclophosphamide23 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 villosa) – 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. Phenoxybenzamine, phentolamine3 Increases toxicity of yohimbine Amobarbital3 Interact Antidepressants5,7,20 Interact Atropine3 Interact Beta blockers3
e.g. Propranolol, penbutolol, metoprolol3 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 Thioxanthenes3
e.g. Chlorprothixene3 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
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