Herb-Medication Interactions: What You Don't Know Can Hurt You.
Americans are taking herbal preparations more then ever, yet rarely inform their doctors, either because they view herbs as innocuous or because they fear the doctor's disapproval. But besides occasional side effects from the herbs themselves, there lies a greater danger--interactions with medications. Researchers are just beginning to explore what they see as the tip of this iceberg.
In the past decade, Americans' use of herbal preparations has increased nearly fourfold. And many of the people taking herbs are older people who take prescription medications as well. While this practice may seem benign-especially if an herb is harmless on its own--recent reports have highlighted serious consequences when some herbs are taken concurrently with drugs. For instance, there have been several cases of organ transplant rejection apparently caused by concomitant use of St. John's wort and cyclospofine, an anti-rejection medication commonly prescribed for transplant patients.
Other interactions are not so straightforward. Since herbal preparations sold in the U.S. are not required to adhere to any standards of potency, purity or efficacy, consumers are often in the dark about what may or may not be in the bottle they buy. One study found that 24% of Chinese herbal preparations evaluated contained unlisted drugs (diuretics or medication for inflammation and pain). Other reports have found the presence of contaminants like lead and arsenic.
Herbal remedies from reputable manufacturers are typically much more reliable, yet there is still the threat of interactions with legitimate drugs and even with over-the-counter medications. The solution is not to forgo herbal preparations, but to communicate with your doctor and your pharmacist about any supplements you are taking. If necessary, you can temporarily stop taking an herb, switch to a different remedy or have your doctor adjust your medicine's dose. You should also ask your doctor about what herbs and supplements to stop taking before surgery.
Below is a sampling of known interactions between herbs and many common medications.
Next month: EN's guide to food-medication interactions.
EN's Guide to Herb-Medication Interactions Interactions are listed by drug category, followed by examples of specific medications (with generic and brand names). For example, garlic interacts with anticoagulants, such as warfarin sodium (Coumadin). But other anticoagulants may interact as well. As always, alert your physician and pharmacist to any over-the-counter medications, herbal remedies and supplements you are taking. Medications What They Do Generic name (sample brand names) Cardiovascular Medications Anti-Arrhythmia Medications: Improve the strength and digoxin (Lonoxicaps, Lanoxin) efficiency of the heart by digitoxin (Crystodigin) regulating heart rate. propranolol HCI (Inderal) Calcium Channel Blockers: Help to regulate heart rate, diltiazem (Cardizem, Dilacor XR, Diltia relax blood vessels. Lower XT, Taztia XT) blood pressure. Ease chest nifedipine (Adalat, Procardia) pain and congestive heart verapamil (Calan, Isoptin, Verelan) failure. Blood Thinners: Inhibit blood clotting. warfarin sodium (Coumadin) Blood Pressure Medications: Decrease blood pressure. clonidine (Catapres) terazosin (Hytrin) Diuretics: Cause water loss, which Thiazide Diuretics: reduces workload on the bendroflumethiazide (Naturetin) heart. chlorothiazide (Diuril) hydrochlorothiazide (Esidrix, Hydrodiuril, Microzide, Oretic ) Loop Diuretics: bumetanide (Bumex) furosemide (Lasix) torsemide (Demadex) spironolactone (Aldactone) Decreases blood pressure amiloride (Midamor) but holds onto potassium. Corticosteroids methylprednisolone (Medrol) Treat inflammation, asthma prednisone (Cordol, Deltasone, Orasone) and arthritis. Diabetes Medications chlorpropamide (Diabenese) Treat type 2 diabetes by glipizide (Glucotol, Glucotrol XL) helping the pancreas glyburide (DiaBeta, Glynase, Micronase) release insulin into the blood stream. Psychotherapeutic Medications Antidepressants: Treat mental depression. Tricyclics: amitriptyline (Elavil, Endep) imipramine (Tofranil) nortriptyline (Aventyl, Pamelor) Selective Serotonin Re-uptake Inhibitors Treat mental depression, (SSRI's): obsessive compulsive fluoxetine (Prozac, Sarafem) disorder, panic disorder and paroxetine (Paxil) social anxiety disorder. sertraline (Zoloft) Barbiturates: Treat anxiety or control phenobarbital (Barbita, Luminal, epileptic seizures. Solfoton) Benzodiazepines: Relieve anxiety. alprazolam (Alprazolam, Intensol, Xanax) diazepam (Valium, Diastat, Dizac) Iorazepam (Ativan) Mood Stabilizers: Treat bipolar disorder. divalproex sodium (Depakote) lithium (Eskalith, Lithobid) Monoamine Oxidase Inhibitors (MAOI's): Relieve mental depression. isocarboxazid (Marplan) phenelzine (Nardil) selegiline (Carbex, Eldepryl) tranylcypromine (Pamate) Other Medications bisacodyl (Dulcolax) Stimulant laxative. cyclosporine (Gengraf, Neoral, Sandimmune, Prevents rejection of SangCya) transplanted organs. Also used for severe rheumatoid arthritis or psoriasis. idinavir (Crixivan) Treat HIV. saquinavir (Fortovase, Invirase) levodopa (Atamet, Larodopa) Treats Parkinson's Disease. methotrexate (Rheumatrex) Used to treat several types of cancer. theophylline (Quibron-T, Respbid, Slo-Bid Treats and prevents the Gyrocaps, Slo-Phyllin, Theo-24, Theobid symptoms of asthma, Duracpas, Theo-Dur, Theolair,, Theo-Time, chronic bronchitis and Uni-Dur, Uniphyl) emphysema. Antibiotics: Fight infection. ampicillin (Polycillin) ciprofloxacin (Cipro) Anticonvulsants: Act on the central nervous ethosuximide (Zarontin) system to reduce number fosphenytoin (Cerebyx) and severity of seizures. phenytoin (Dilantin) Estrogen Replacement: Female hormone conjugated estrogens (Premarin) replacement. estradiol (Alora, Climara, Depogen, Estraderm) Oral Contracentives: To prevent pregnancy. levonorgestrel & ethinyl estradiol (Alesse, Levlen, Levlite) norethindrone & ethinyl estradiol (Brevicon, Genora, Jenest, Ortho 7/7/7) Over-the-Counter Medications acetaminophen (Anacin-Free, Panadol, Pain relief. Tylenol) aspirin (Anacin, Bayer, Excedrin) Pain relief. Medications Selected Herb Interactions Generic name (sample brand names) Common name (Latin name) Cardiovascular Medications Anti-Arrhythmia Medications: * Siberian ginseng digoxin (Lonoxicaps, Lanoxin) (Eleutherococcus digitoxin (Crystodigin) senticosis) may falsely elevate digoxin levels. * The following contain digoxin-like substances and may contribute to digoxin toxicity: * milkweed * hawthorne leaf with flower (Crategus spp.) * The following decrease digoxin concentrations in the blood: * St. John's wort (Hypericum perforatum) * guar gum slows absorption Calcium Channel Blockers: * The following cause diltiazem (Cardizem, Dilacor XR, Diltia potassium losses and may XT, Taztia XT) trigger the toxicity of nifedipine (Adalat, Procardia) certain cardiac propranolol HCI (Inderal) medications: verapamil (Calan, Isoptin, Verelan) * aloe latex and drug aloe (not juice) (Aloe vera) * buckthorn bark and berry (Rhamnus frangula) * cascara sagrada bark (Rhamus purshiana) * senna leaf (Cassia senna) Blood Thinners: * The following have warfarin sodium (Coumadin) anticoagulant effects that may exacerbate the drug's effect, possibly triggering post-operative bleeding: * dong quai (Angelica sinensis) * fenugreek (Trigonelle foenum-graecum) * feverlew (Tanacetum parthenium) * garlic (Allium sativum) * ginger (Zingiber officinale) * ginkgo (Ginkgo biloba) may also cause brain hemorrhage * ginseng (Panax ginseng) may also trigger blood clots Blood Pressure Medications: * kava (Pipermethysticum) clonidine (Catapres) may cause lethargy and terazosin (Hytrin) disorientation. * The following increase blood pressure, counteracting the effects of the medication: * ma huang (Ephedra sinica) * yohimbe (Pausinystalia yohimbe) * fenugreek (Trigonelle foenum-graecum) * licorice (Glycyrrhiza glabra) also increases sodium and decreases potassium. Diuretics: * fenugreek (Trigonelle Thiazide Diuretics: foenum-graecum) has bendroflumethiazide (Naturetin) diuretic properties and chlorothiazide (Diuril) may exacerbate water loss. hydrochlorothiazide (Esidrix, * ginkgo (Ginkgo biloba) may Hydrodiuril, Microzide, Oretic) raise blood pressure with Loop Diuretics: thiazide diuretics. bumetanide (Bumex) furosemide (Lasix) torsemide (Demadex) spironolactone (Aldactone) * yohimbe (Pausinystalia amiloride (Midamor) yohimbe) may counteract drug's effect. Corticosteroids methylprednisolone (Medrol) * betel nut (Areca catechu) prednisone (Cordol, Deltasone, Orasone) counteracts effects of steroids. * ginseng (Panax ginseng) may cause steroid toxicity. * licorice (Glycyrrhiza glabra) increases prednisone levels in blood and contributes to high blood pressure. Diabetes Medications chlorpropamide (Diabenese) * The following may decrease glipizide (Glucotol, Glucotrol XL) blood sugar, leading to glyburide (DiaBeta, Glynase, Micronase) hypoglycemia: * fenugreek (Trigonelle foenum-graecum) * ginseng (Panax ginseng) * karela or bitter melon (Morodica charantia) * echinacea (Echinanacea purpurea) alters metabolic control in people with diabetes. Psychotherapeutic Medications Antidepressants: * ginseng (Panax ginseng) Tricyclics: may cause mania. amitriptyline (Elavil, Endep) * The following may enhance imipramine (Tofranil) the effects of tricyclics, nortriptyline (Aventyl, Pamelor) causing restlessness: * ma huang (Ephedra) * St. John's wort (Hypeifcum perforatum) * ginkgo (Ginkgo biloba) * yohimbe (Pausinystalia yohimbe) may cause high blood pressure with tricyclics. Selective Serotonin Re-uptake Inhibitors * The following may enhance (SSRI's): the effects of SSRI's, fluoxetine (Prozac, Sarafem) causing restlessness: paroxetine (Paxil) * St. John's wort sertraline (Zoloft) (Hypericum perforatum) * mahuang (Ephedra) Barbiturates: * The following enhance the phenobarbital (Barbita, Luminal, effects of medication, Solfoton) causing sleepiness and lethargy: * valerian (Valeriana officinalis) * St. John's wort (Hypericum perforatum) * kava (Piper methysticum) Benzodiazepines: * The following enhance the alprazolam (Alprazolam, Intensol, Xanax) effects of medication, diazepam (Valium, Diastat, Dizac) causing sleepiness and Iorazepam (Ativan) lethargy: * kava (Piper methysticum) * valerian (Valeriana officinalis) Mood Stabilizers: * psyllium (Plantago avato) divalproex sodium (Depakote) decreases lithium lithium (Eskalith, Lithobid) concentration. * ginseng (Panax ginseng) may cause mania. Monoamine Oxidase Inhibitors (MAOI's): * St. John's wort (Hypericum isocarboxazid (Marplan) perforatum) slightly phenelzine (Nardil) inhibits effect of drug. selegiline (Carbex, Eldepryl) * yohimbe (Pausinystalia tranylcypromine (Pamate) yohimbe) increases toxic effects of medication. * ma huang (Ephedra) enhances action of MAOI's, possibly resulting in life-threatening high blood pressure, high fever and coma. * ginseng (Panax ginseng) may cause headache, mania, tremors. Other Medications bisacodyl (Dulcolax) * The following anthraquinone-containing herbs can enhance laxative effect: * aloe (Aloe barbadensis) * cascara sagrada (Rhamnus pershianus) * senna (Senna alexandrina) * yellow dock (Rumex cifspus) cyclosporine (Gengraf, Neoral, Sandimmune, * St. John's wort (Hypericum SangCya) perforatum) decreases amount of drug in blood, which may result in transplant rejection. * echinacea (Echinacea pupurea) alters immune function, possibly counteracting drug's effects. idinavir (Crixivan) * The following can decrease saquinavir (Fortovase, Invirase) effectiveness of the drug: * garlic * St. John's wort (Hypericum perforatum) levodopa (Atamet, Larodopa) * kava (Piper methysticum) may decrease drug's effectiveness. methotrexate (Rheumatrex) * echinacea (Echinacea pupurea) may damage the liver. theophylline (Quibron-T, Respbid, Slo-Bid * St. John's wort (Hypericum Gyrocaps, Slo-Phyllin, Theo-24, Theobid Perforatum) can inhibit Duracpas, Theo-Dur, Theolair,, Theo-Time, drug's effectiveness. Uni-Dur, Uniphyl) Antibiotics: * The following decrease ampicillin (Polycillin) drug availability: ciprofloxacin (Cipro) * dandelion (Taraxacum mongolicum) * fennel (Foeniculum vulgare) * khat (Catha edulis) Anticonvulsants: * The following may ethosuximide (Zarontin) interfere with seizure fosphenytoin (Cerebyx) control: phenytoin (Dilantin) * evening primrose oil (Primula veris) * ginkgo (Ginkgo biloba) * kava (Piper methysitcum) Estrogen Replacement: * saw palmetto (Seronoa conjugated estrogens (Premarin) serrulata) can exacerbate estradiol (Alora, Climara, Depogen, breast tenderness Estraderm) Oral Contracentives: * The following may increase levonorgestrel & ethinyl estradiol blood pressure: (Alesse, Levlen, Levlite) * licorice (Glycyrrhiza norethindrone & ethinyl estradiol glabra) (Brevicon, Genora, Jenest, * St. John's Wort Ortho 7/7/7) (Hypericum perforatum) may also cause breakthrough menstrual bleeding. Over-the-Counter Medications acetaminophen (Anacin-Free, Panadol, * ginkgo (Ginkgo biloba) Tylenol) may cause brain hemorrhage. aspirin (Anacin, Bayer, Excedrin) * tamarind (Tamarindus jadica) increases blood levels of aspirin. * ginkgo (Ginkgo biloba) may cause prolonged bleeding and eye hemorrhage. * garlic (Allium sativum) can cause prolonged bleeding. Sources: An EN original compilation of information from journal articles and experts in the field. [C] Copyright, 2001 by Environmental Nutrition, Inc., 52 Riverside Drive, New York, NY 10024; www.environmentalnutrition.com
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|Date:||Oct 1, 2001|
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