Potential Drug Interactions and Adverse Effects of Commonly Used Herbal Remedies and Alternative Medications

Capsaicin Glucosamine & Chondroitin
Chamomile Hawthorne
Echinacea Kava Kava
Ephedra Kelp
Feverfew Licorice
Garlic Melatonin
Ginger Phytoestrogens
Ginkgo Saw Palmetto
Ginseng St.John's Wort
Gossypol Valerian


General Info
Capsaicin is the active ingredient in the extract of hot peppers. It is most concentrated in the rib or membrane, less in the seeds, least in the flesh. Capsaicin for medicinal use comes from Capsicum fructescens, a species of the cayenne pepper.
Mechanism of Action
Capsaicin depletes substance P in afferent type C sensory nerve fibers and affects only proprioception. Unlike other treatments for neuropathy, such as local anesthetics, opiates, anti-seizure medications or tricyclic antidepressants, capsaicin specifically treats pain without impairing other aspects of the nervous system. In incomplete depletion of substance P from suboptimal use, it may cause parodoxical increase of pain.
Post-herpetic neuralgia, post-mastectomy pain, hemodialysis-associated pruritus, psoriatic itching and pain, painful neuropathies, especially diabetic neuropathy, and other superficial neuropathies.
Creams of varying potency from 0.01% and 0.075% applied 4-5 times daily for at least four weeks. Because of local side effects, it is advisable to start with low potency creams and increasing in potency as tolerated. Less frequent application, such as once or twice daily, can actually lead to increased pain. Older patients, especially those with long-standing post-herpetic neuralgia, may require several years of therapy and may even need lifelong treatment.Capsaicin is also available as fresh and dried peppers, capsules, tablets, and tinctures.
Because of potential respiratory toxicity, avoid concentrations greater than 0.1%. Higher concentrations are also more likely to cause local chemical irritation. Wear gloves during applications, avoiding contact with eyes and mucous membranes; do not use on open abrasions and open wounds.
Approved for external application, capsaicin is also available as tablets, capsules and tinctures.
Capsaicin and Dyspepsia
In a small trial in Italy (Dr. Mauro Bortolotti et al, University of Bologna), 30 patients with functional dyspepsia were randomized on daily capsules of 2.5 g of red pepper or placebo. The capsaicin content (trans-8-methyl-N-vanillyl-6-nonenamide) was 0.7 mg/g of red pepper power. After 3 weeks, upper gastrointestinal symptoms of epigastric pain, fullness, nausea and early satiety were all significantly reduced in the capsaicin group and not in the placebo group. The mechanism of action is believed to be the desensitization of gastric nociceptive C fibers, which carry pain sensations to the central nervous system. (NEJM.346[12]:947-48,2002)
Clinical Capsules. Internal Medicine News. May15,2002

Matricaria recutita
(1) As a sedative, antispasmodic, and antiseptic. (2) For peptic ulcers; mucous membrane and anogenital inflammation. (3) To promote wound healing.
Use with caution in patients taking other sedating medications because of possible excessive excessive sedation, drowsiness, loss of coordination, and trouble driving or operating machinery. An active ingredient in chamomile is coumarin.
It is unknown whether chamomile affects coagulation and if there is significant interaction between chamomile and warfarin.
Monitor chamomile use in patients also taking warfarin.

Echinacea purpurea
General Info
A perennial American wildflower belonging to the daisy family, found in the Plains states. Different parts of the plant contain different chemicals; e.g., isobutylamides are in the roots of augustifolia and purpurea; cichoric acid is in the above-ground parts of purpurea.
Mechanism of Action
Stimulation of phagocytosis by macrophages; inhibition of hyaluronidase; increase fibroblast number and properdin levels and possible increase of interferon production.
An immunostimulant used to prevent or treat the common cold and flu. Topically for stings, bites, wounds, burns. In Europe, available for parenteral use.
There has been controversy with echinacea use, with some studies showing benefit while other show none. From a meta-analysis of 14 published, randomized and placebo controlled trials, users of echinacea suuplements reduced their odds of developing the common cold by more than half. In those who have caught a cold, echinacea supplements cut a mean of 1.4 days from the duration of illness.
      Prophylactic use of echinacea reduced the incidence of naturally occurring colds by 65%, compared with placebo.
900 mg (180 drops) of an ethanolic extract of E. Purpurea roots significantly reduced the severity and duration of symptoms of flu-like infections. 450 mg (90 drops) were no more effective than placebo.
Possible reactions in those with a history of allergy to the daisy family. No documented drug interactions. Patients receiving immunosuppressives (cyclosporine) should be monitored for decreased effectiveness when used with echinacea. Also, long-term use of Ecchinacea may cause immunosuppression. Should not be used in patients with autoimmune diseases or progressive systemic diseases as: SLE, TB or MS. German Commission E monograph states that "the metabolic condition in diabetes can decline upon parenteral application." Some products may be adulterated with another similar herb, Parthenium intergrifolium L, which has no pharmacologic activity.
Use for more than 8 weeks raises concerns for postoperative immunosuppression which may theoretically cause postsurgical complications, including impaired wound healing and opportunistic infections. There is also concern for hepatotoxicity.

Ephedra sinica, Ephedra intermedia, Ephedra equisetina, Ephedra distachya
General Info
A naturally occurring substance in the Chinese herbal Ma-Huang. Ephedrine constitutes 30 to 90 percent of the alkaloids of Ephedra species. Ephedrine alkaloids are amphetamine-like compounds with powerful stimulant effects on the heart and nervous system, increasing the heart rate and blood pressure, decreasing the appetite and providing an sense of energy-boosting.
Ephedra (Ma-Huang) is found in many herbal weight-loss products and has been called the "hebal fen-phen," promoted in some weight loss clinics as the alternative to fenfluramine (Pondimin) and dexfenfluramine (Redux), prescription anorexiants recently removed from the U.S. market.
      Ephedrine containing products are also marketed as decongestants, bronchodilators, stimulants and energy-boosters. As a stimulant, it has been marketed as an ergogenic drug for enhancement of athletic performance and body building efforts. It has also been available as "herbal ecstasy" with its ability to induce euphoria, heighten awareness and sexual sensations.
Available evidence show a significant and unreasonable risk of illness and injury from dietary supplements containing ephedra. Adverse reactions are insomnia, nervousness, tremor, headaches, hypertension, seizures, arrhythmias, heart attack, stroke and death. Should not be used with MAOIs (monoamine oxidase inhibitors, ie, phenelzine, tranylcypromine), cardiac glycosides, and antiarrhythmic agents. FDA warnings have been issued because of its causative relationship with hypertension, seizures, and death. It should not be used in patients with a history of hypertension, heart disease, arrhythmias, glaucoma or stroke. Although dosage limit has been suggested at 8 mg every 6 hours (24 mg per day) for ephedra alkaloids, serious side effects may occur at much lower doses (4-20 mg per day).
      An NIH report concluded that ephedra is associated with higher risks of mild-to-moderate side effects such as heart palpitations, psychiatric and upper gastrointestinal effects and symptoms of autonomic hyperactivity (tremors and insomnia).
While ephedra-products make up less than 1% of all dietary supplement sales, these products account for 64% of adverse events associated with dietary supplements.
Patients on ephedra who are later on halothane anesthesia may be a higher risk for ventricular arrhythmias. There is also concern for hypersensitivity myocarditis. Ephedra should be discontinued at 24 - 48 hours before surgery.

Tanacetum parthenium
Treatment of migraine headaches, fever, and menstrual problems. It is thought to work by decreasing the production of prostaglandins through a mechanism different from NSAIDs.
Unknown interaction with aspirin or NSAIDs.
It appears to inhibit platelet activity and should be used with caution by patients receiving anticoagulant therapy (eg. warfarin, dicoumarol, heparin).

Allium sativum
Lowers total cholesterol, LDL, triglyceride levels, and blood pressure, and raises HDL cholesterol levels. It is reported to have antibacterial, antifungal, antithrombotic, hypoglycemic, antiinflammatory, and anticancer activity.
When garlic is used in combination with other lipid-lowering agents (eg, atorvastatin [Lipitor], fluvastatin [Lescol], pravastatin [Pravachol], simvastatin [Zocor], gemfibrozil [Lopid], fenofibrate [Tricor], niacin [Niaspan], hypoglycemic agents (eg, insulin, glyburide, glipizide, troglitazone [Rezulin], glimeripide [Amaryl], chlorpropamide [Diabenese], tolbutamide [Orinase], or antihypertensive agents, their effects may be increased.
Garlic can also be used to decrease platelet aggregation; thus, combined use with anticoagulants may increase the risk of bleeding. Isolated reports have suggested that garlic may increase international normalized rations (INRs). However, none of these potential drug interactions has been adequately documented.
The potential for irreversible inhibition of platelet aggregration warrants stopping its use at least 7 daqys prior to surgery, especially if postoperative bleeding is of particular concern or if other platelet inhibitors are used.

Zingiber officinale
Used mostly for motion sickness as an antiemetic / antinauseant. Also used as an antispasmodic and antiinflammatory agent. In a controlled trial in the U.S. with college students as the subjects, compared with placebo and diphenhydramine, ginger was most effective for reducing experimentally induced motion sickness (students were spun in a chair). Fifty percent of the subjects who ingested ginger remained in the chair for 6 minutes, but none treated with either placebo or diphenhydramine was able to do so. In Germany, ginger was approved for use in motion sickness and as a digestive aid.
Ginger may decrease thromboxane production and cause prolong bleeding time and platelet inhibition. Therefore, should be used with caution by patients receiving anticoagulant therapy.

Active Ingredients
Flavone glycosides have antioxidant properties: terpenoids (ginkgolides) improve circulation; bilobalides have neuroprotective properties.
It alters vasoregulation, modulates neurotransmitter and receptor activity and inhibits PAF (platelet activating factor).
Ginkgo is promoted to treat Alzheimer's disease and dementia, improve memory and cognitive function, cerebral and peripheral blood flow (claudication), tinnitus and vertigo.
Some Ginkgo products may contain a neurotoxin (Ginkgo toxin) that might increase the risk of seizures. Caution is advised in patients requiring anticonvulsant therapy (eg, carbamazepine, phenytoin, phenobarbital) or agents that might lower the seizure threshold (eg, amitriptyline, imipramine, molindone [Moban], promethazine [Phenergan], tramadol [Ultram], maprotiline [Ludiomil], bupropion [Wellbutrin, Zyban]).
Ginkgo therapy has been associated with decreased platelet aggregation and spontaneous bleeding, and should be used with caution by patients receiving anticoagulants, vitamin E, aspirin, NSAIDs and other drugs or herbal medicinals with antiplatelet or anticoagulant effects. A case of spontaneous bilateral subdural hematoma has been attributed to ginkgo us.
The effect on PAF and platelet aggregation may contribute to perioperative bleeding. Ginkgo use should be discontinued at least 16 hours before surgery.

The most controversial of herbs, it has claimed benefit for just about every human ailment with little scientific evidence to support its myriad of claims. It has touted as an "adaptogen" (to build up vitality and resistance to stress) and as an aphrodisiac. There are claims on lowering total and LDL cholesterol levels. Some ingredients raise blood pressure, and some lower it. Unfortunately, as in many herbals claiming medicinal benefits, there is no quality control and many preparations contain little or no ginseng. One study looked at 10 'ginseng' products and found 7 contained no ginseng at all. A study analyzed 54 ginseng products; 60% contained less than the therapeutically effective levels, and an astounding 20% contained no active ingredient. In another study, on 18 quality of life measures, ginseng was equivalent to placebo; four quality of lilfe measures improved, but clinical relevance was nonexistent.
Nervousness and excitation can occur in the first few days of intake. Overuse can cause headache, epistaxis, insomnia, and palpitations. Because of ginseng's unpredictable effect on BP, hypertensive patients should be cautioned of its use. Estrogenic effects can cause vaginal bleeding and mastalgia; patients on hormonal therapy should avoid its use. Ginseng can also adversely interact with monoamine oxidase inhibitor phenelzine. In general, patients should be discouraged from using ginseng for longer than 3 months.
Probably has an interaction with warfarin. Patients on warfarin and dietary supplements containing this herb should be closely monitored for a possible interaction.
May have an irreversible effect on platelets and should be discontinued at least 7 days before surgery.

It is associated with renal loss of potassium, resulting in hypokalemia.  Avoid intercurrent use of gossypol with hydrochlorothiazide or furosemide or digoxin.

Both components of the cartilage matrix, have been touted as pain relievers as well as agents that might actually slow the progression of osteoarthritis.

Studies show glucosamine stimulates the cartilage cells to synthesize glycosaminoglycans and proteoglycan ground substance. For the past three decades, it has been thought to be beneficial for osteoarthritis. However studies to support this were lacking - until recently. Studies using glucosamine sulfate, 1500 mg day, suggest a beneficial effect on arthritis of the knee, hip, and back. A study showed a slight but significant increase in joint space and less progression of OA of the knees, with improvement in scores of pain and physical function. Glucosamine sulfate seems to be more effective, faster acting and provides far more impressive results and greater overall benefit than chondroitin. Recent studies have shown that glucosamine does not adversely affect blood sugar control.

Glucosamine: 1500 mg daily in 3 divided doses; chondroitin sulfate, 800 to 1,600 mg daily, the lower dosing given to patients under 120 pounds.
Glucosamine is derived from oysters and the chitin of crab shells and chondroitin is derived from shark cartilage and bovine trachea. Because of the nature of these sources, allergic reactions are possible.

Crataegus laevigata, Crataegus monogyna, Crataegus pinnatifida
Hawthorne is used to treat heart disease, angina, hypertension, and sleep disorders. High doses of hawthorne can cause depression of the CNS and hypotension.
Should be used with caution in patients receiving antihypertensive medications and other drugs reported to cause depression of the CNS (eg, antihistamines, tricyclic antidepressants, anticonvulsants, benzodiazepines, antipsychotics).

Piper methysticum
Kava kava is used to treat sleep disorders, anxiety, and menopausal symptoms. In the U.S., the anxious and the insomniacs spent more than $50 million on variety of kava products: drinks and teas, capsules and candies.
When used with other sedative agents (eg, benzodiazepines, antihistamines, anticonvulsants, tricyclic antidepressants, antipsychotics), it may cause excessive sedation, drowsiness, loss of coordination, and trouble driving or operating machinery. Kava dermopathy has been reported with the use of kava as a traditional South Pacific beverage.
An alert has been issued because of recent increasing reports of severe liver damage in kava users with one patient needing a liver transplant. Patients who have liver disease or who consume moderate amounts of alcohol should avoid use of kava. Users should avoid daily use of more than four weeks. The recommended dose is 60 to 120 mg of the active ingredient, kavalactone.
A specific kavalactone, kawain, appears to decrease thromboxane 2 production and inhibit cyclo-oxygenase, indicating that kava may have significant inhibitory effect on platelet aggregation.
It has hypnotic and sedating effects and should be discontinued at least 24 hours before surgery.

Its prolonged use is associated with hyperthyroidism; should be considered a possible etiology of atrial fibrillation with patients with apparent lone AF. Discourage use of kelp with amiodarone.

Glycyrrhiza glabra, Glycyrrhiza uralensis
Liquorice is used as an antiinflammatory agent and for the treatment of peptic ulcers. This liquorice is not, however, found in most candy that is labeled as "licorice."
Liquorice has mineralocorticoid properties and may cause pseudoaldosteronism with sodium and water retention and hypokalemia. Therefore, liquorice may decrease the effectiveness of antihypertensive agents and diuretics. In addition, it may increase the risk of hypokalemia when used with non-potassium sparing diuretics (eg, chlorothiazide [Diuril], furosemide [Lasix], bumetanide [Bumex], torsemide [Demadex], metolazone [Zaroxolyn]). The effects of digoxin (Lanoxin) and other digitalis glycosides can be increased if the liquorice does cause hypokalemia. With low potassium, digitoxicity may occur with therapeutic digoxin levels.

Mel, Melatonex
General Info
Pineal gland hormone whose synthesis / secretion is controlled by the prevailing light-dark environment, via the hypothalamic suprachiasmatic nuclei (SCN). It is synthesized from serotonin. Nocturnal secretion of melatonin and its main metabolite 6-sulphatoxy melatonin (6-hydroxy melatonin sulfate) is highest in young children and falls with age.
      In the US, synthetic melatonin is sold over-the-counter as a "food supplement" because it is naturally found in small amounts in some foods (e.g., bananas and rice). Like other supplements sold in the US market before October 15, 1994, melatonin was exempted from federal drug laws and was considered as a food supplement by the Dietary Supplement Health and Education Act of 1994. There are no natural extract versions of melatonin currently available. The US retail market for melatonin is estimated at $200-350 million annually.
      Some studies have suggested melatonin may enhance immune response by increasing IL production by T-helper cells and free radical scavenging.
Although melatonin has been studied for cyclic mood disorders, sexual maturation and reproduction, its main use is for "jet lag" and as a sleep aid. Studies supports the use of melatonin for short-term treatment of jet lag. Caution must be exercised since melatonin is a recombinant human hormone, and the safety of long-term use has not been evaluated. A recommended jet lag protocol is: 0.3 mg synthetic melatonin tablets: (1) For eastward travel, take preflight melatonin in the late afternoon of departure and take post-flight melatonin for four days after arrival at local bedtime. (2) For westward flights, take melatonin at local bedtime for four days after arriving with a second smaller dose if there is early morning awakening. It should not be taken for more than one month at a time and not more than 0.5 mg per day, as long-term studies are not yet available. ·
Adverse Effects
Sleepiness, impaired libido, mild depression at greater doses. Nausea, headache, nightmares. Possible decreased alertness and reproductive effects. Drug interactions with beta-blockers, CNS depressants, androgens and estrogens, SSRIs and MAOIs.
Use only synthetic melatonin and start with the lowest possible dose (available as 0.3, 1.5, 3.5, 10 mg) 1-2 hours before bedtime.
Do not use during pregnancy, lactation, in children, or if trying to conceive. Do not use if a patient has immune-system cancers. Do not use if a patient is on any drug that may interact with melatonin.

General info
Phytoestrogens are nonsteroidal plant compounds resembling estradiol (E2), with both estrogenic and anti-estrogenic activities. They are found in many fruits, vegetables and grains, but leguminous seeds are especially rich in these compounds.
      There are 3 main classes of phytoestrogens: flavanoids, coumestans, and resorcyclic acid lactones. Isoflavones have the most potent hormonal-like activity and an extensive range of biological activities in the body. More than 1,100 isoflavanoids are known, exclusively found in leguminous seeds such as soybeans, chickpeas, lentils and beans. The most important isoflavones are genistein, daidzein, glycetin, formonetin, and biochanin. Soybeans, besides being an excellent sourse of isoflavones, is also rich in daidzein and genistein.
Ipriflavone (7-isopropoxyisoflavone) is a synthetic isoflavone derivative used in several countries in Europe, in particular Italy, and in Japan, for prevention and treatment of osteoporosis. In the US, ipriflavone (IP) is available as a dietary supplement.


Phytoestrogens are used to treat the symptoms of menopause. Phytoestrogens (eg, coumestrol, genistein, daidzein, biochanin A, formononetin) can be found in foods such as soy, lentils, broad beans, chick-peas, and red clover, as well as nonprescription products (eg, Promensil).
      Recent studY: Phytoestrogen supplements for the treatment of hot flashes: The Isoflavone Clover Extract (ICE) Study: a randomized controlled trial. JAMA.2003;290:207-214. A randomized controlled trial of 252 menopausal women, aged 5-60, with about 35 hot flashes per week, using Promensil (82 mg/d of isoflavones) and Rimostil ( 57 mg/d of total isoflavones) showed no clinical effect on hot flashes and other menopause symptoms compared to placebo.
Isoflavone consumption in Eastern countries is in the order of 20-150 mg/d (average 40 mg/d), as compared with 2-5 mg/d in Western countries. In adults consuming 50 mg/d total isoflavones (such as found in traditional Japanese diet) a plasma isoflavone concentration of 50-800 ng/ml may be achieved, far exceeding normal plasma estradiol concentrations (40-80 pg/ml).
      Persons with risk factors for osteoporosis should consume about 14 servings of soy protein per week. This would provide an average of approximately 16-20 g of soy protein/d with 32-40 mg of isoflavones/d. Persons with osteoporosis should consume 21 servings of soy protein per week, which would yield about 24-30 g of soy protein and 48-60 mg of isoflavones daily.
      The average dose recommendation of isoflavone dietary supplements is 40 mg/d of aglycone isoflavones. Doses of 40-160 mg/d have been used in humans with a favorable side effect profile. The usual dose of IP (ipriflavone) is 200 mg tid.
Some of the phytoestrogens do have significant activity at the estrogen receptors. When phytoestrogens are used in combination with estrogen-containing products, the risk of estrogen-related side effects (eg, nausea, bloating, breast fullness or tenderness) may be increased. Isoflavone dietary supplements should be avoided in pregnancy and lactation.There are concerns with the use of high doses of isoflavones by patients with hormone-sensitive cancers. Until use in cancer patients is more carefully evaluated, concentrated supplements should be taken with caution. It is unknown if phytoestrogens will decrease the effectiveness of tamoxifen (Nolvadex) or raloxifene (Evista).

Serenoa repens
Saw palmetto is used for the treatment of benign prostatic hypertrophy and as a diuretic and urinary antiseptic. It appears to inhibit both dihydrotestosterone binding at the androgen receptors and 5-alpha-reductase activity on testosterone.
Whether saw palmetto can increase or decrease the effectiveness of doxazosin (Cardura), terazosin (Hytrin), and finasteride (Proscar) is unknown.

Hypericum perforatum
The mechanism of action of St. John's wort has not been fully established but likely is involved with inhibition of serotonin, norepinephrine and dopamine reuptake. St. John's wort also utilizes the cytochrome P450 system which affects the metabolism of more than 50% of all drugs. It also inhibits GI absorption, including the P-glycoprotein enzyme system with wide-reaching effects. It is used for the treatment of anxiety, depression, and sleep disorders.
It is commonly stated to be a MAOI and a selective serotonin reuptake inhibitor. If the MAOI properties were significant, we should have seen reports of elevated blood pressure in patients concomitantly receiving decongestants, Ma Huang, and other sympathomimetic products. However, caution should be used if the patient is taking St. John's wort and a sympathomimetic agent or other MAOIs (eg, phenelzine [Nardil], selegiline [Carbex, Eldepryl], furazolidine [Furoxone]), especially in patients with hypertension or arrhythmias.
        The risk of serotonin syndrome may be increased when St. John's wort is used in combination with other serotonergic agents: tricyclic antidepressants, SSRIs (Prozac, Paxil, Zoloft), lithium, dextrometorphan. The serotonin syndrome is a hyperserotinergic condition that can have very dangerous side effects. Signs and symptoms of serotonin syndrome may include euphoria, drowsiness, sustained rapid muscle contraction and relaxation in the ankle, causing abnormal movements of the foot; clumsiness, restlessness; dizziness; sweating, muscle twitching, rigidity, high body temperature; mental status changes, including confusion and hypomania; shivering, diarrhea, and loss of consciousness.
St. John's wort has had documented interactions with cyclosporine, amitriptyline, digoxin, indinavir (49 % to 99% reduction in serum drug levels), warfarin, phenprocoumon, theophylline, oral contraceptives, SSRIs, and loperamide. In addition, St. John's wort may increase the risk of photosensitivity reactions when used with other photosensitizing agents (eg, tetracycline, doxycycline, fluoroquinolones, interferons, felbamate [Felbatol], griseofulvin, isoretinoin [Accutane], porfimer [Photofrin]).
May increase the metabolism of drugs utilized in perioperative care, including cyclosporine, midazolam, lidocaine, and calcium channel blockers. Use should be discontinued at least 5 days before surgery.

Valeriana officinalis
General Info
A traditional herbal sleep remedy. Chemical constituents are sesquiterpenes of the volatile oil (valerenic acid), iridoids (valepotriates), furanofuran lignans, free amino acids, and alkaloids. The sesquiterpine components are believed to be responsible for its biologic effects. Studies have suggested direct sedative effects (valepotriattes, valeric acid) and interaction with neurotransmitters such as GABA.
      As a food supplement, it is not subjected to regulatory control beyond labeling requirements. FDA classifies valerian as GRAS.
Has the characteristic odor of dirty socks.
Anxiolytic, sedative, and tranquilizer. It appears to be a safe sedative/hypnotic choice for mild to moderate insomniacs wihtout the hangover-sleepiness of benzodiazepines. It is also used for mild anxiety; however supporting data is limited.
      Although with poorly defined effects on GABA neurotransmission, it may attenuate benzodiazepine withdrawal symptoms.
Side Effects
Some patients report mild headache (occasionally migraine-type) or gastrointestinal disturbances (usually nausea) with valerian use. There have been at least five reports of hepatotoxicity; these were not dose related and were considered idiosyncratic (Drug Saf. 17[5]:342-56, 1997). There has been one case report of a withdrawal syndrome similar to that seen with benzodiazepines in a man who used high doses of the herb for many years (JAMA 280[18]:1566-67, 1998).
      Long-term safety studies have not yet been done with valerian. In theory, valerian could interact with barbiturates, benzodiazepines, opiates, or alcohol.
      A report of an overdose of valerian with 40-50 capsules (20 times the recommended dose) resulted in mydriasis, fatigue, abdominal cramping, chest tightness, lightheadedness, and foot-hand tremor that resolved in 24 hours. Lab tests, including liver funtion tests, were normal.
No significant herbal/drug interactions with valerian have been reported.
It may potentiate the sedative effects of barbiturates, anesthetics and CNS depressants.
Although not synergistic with alcohol, concomitant use is not recommended.
Withdrawal may occur with sudden cessation after high-dosage long-term use.
Use in pregnancy is not recommended.
Label caution: In one label testing of 17 valerian products, only 9 products passed. Four had no detectable level of expected valerinic acid, another four had about half of claimed amounts. Extract products fared much better than root powder source.
Doses and Recommendations
Use 300-600 mg one hour before bedtime for insomnia, bid for anxiety. Must contain 0.5% essential oil (valerenic acid).
      For use as dried herbal valerain root, 2 to 3 g is soaked in one cup of hot water for 10-15 minutes and ingested 1/2 to 2 hours before bedtime.
Valerian produces dose-dependent sedation and hypnosis and can potentiate the sedative effects of anesthetics and adjuvants such as midazolam. Taper use over several weeks before surgery as sudden discontinuation may result in a benzodiazepine-like withdrawal.


Echinacea May Protect Against the Common Cold http://www.internalmedicinenews.com/article/PIIS1097869007710570/fulltext. Volume 40, Issue 17, p40 (1 September 2007)
Valerian for Insomnia
Nancy Walsh, Internal Medicine News. April 1, 2004
Eight Herbal Agents To Stop Before Surgery
Mitchel Zoler. Internal Medicine News. May 1, 2003
New Report may signal end of ephedra products
Jeremy Moore. Today in Cardiology. May 2003
Susan Hadley MD, Judith Petry MD. American Family Physician. April 15,2003. Vol 67, No 3.
Herb-drug Interactions
Robert Bonakdar MD, Patient Care/January 2003 (www.patientcareonline.com)
Potential Drug Interactions with Common Herbal Remedies
Daniel E. Baker, PharmD.
Capsaicin (Hot Pepper Extract for Neuropathic Pain)
David Schiedermayer, MD, FACP
Glucosamine: Hope or Hype?
Patient Care. July 15, 1999
Q&A with Roland Moskowitz, MD
Consultant. June 2000
Melatonin for Jet Lag
Joshua Ofman, MD & Jay Udani, MD
Phytoestrogens : Use in Osteoporosis
Nicole Nisly, MD and Teresa Klepser, PharmD. Alternative Medicine Alert. Dec 1999
Herbal Remedies: Adverse Effects and Drug Reactions
Melanie Cupp, Pharm.D.American Family Physician / Mar 1, 1999