Concerns about herb-drug interactions are often not based on rigorous research. about possible interactions between black cohosh and various medications. Many medicinal herbs and pharmaceutical drugs are therapeutic at one dose John's wort are two popular herbal products marketed to treat liver disorders and . Several cases of possible herb drug interactions have been reported (Cupp et . Herbs involved in drug interactions – or that have been evaluated in pharmacokinet. Chinese medicine to prevent and treat cardiovascular conditions, .. The possible interactions with conventional medicines are the most.
Should Possible Herbal-Drug Interactions? Handle How I
Examples of important medicines extracted from botanicals include reserpine , morphine , penicillin , and vinca alkaloid anti-cancer drugs. Today, herbal supplements and nutraceuticals can be purchased over-the-counter OTC and may be labeled "all-natural", but that does not always mean they are safe.
While these products are intended to boost health, and may make claims to that effect, robust clinical studies may be lacking. Herbal supplements are sold in many different forms - dried leaves for teas, powdered, as capsules or tablets, or in solution. The FDA does not apply the same effectiveness and safety studies used for prescription drugs to herbals, dietary supplements, and their manufacturers.
The FDA can and does seize and remove from the market tainted, contaminated or unsafe dietary supplements when they are aware of problems; kratom is one example that has been involved in many seizures. Herbal supplements are not subject to review by the FDA and their use can often be risky. Consumers need to understand that even though the label may say "natural", these products are not always safe , as demonstrated by "all natural" alternatives for erectile dysfunction that the FDA found contained actual prescription medications.
Even though herbal supplements may be from plant or herb sources, the active ingredients can still be potent chemicals. Because of this, herbal supplements can have drug interactions, even with each other or with food or alcohol. Unfortunately, these products are not labeled with safety warnings, and it is difficult for a consumer to know if an interaction may occur.
You can search for herbal supplement-drug interactions here , and always check with your doctor or pharmacist for clarification. Black cohosh is a shrub-like plant found in North America. Black cohosh is often used for menopausal disorders "hot flashes" , painful menstruation, uterine spasms, and vaginitis.
However, prescription drugs broken down by certain liver enzymes may accumulate in the body and lead to toxicity if used with black cohosh. There is concern that black cohosh might also be toxic to the liver and may enhance liver toxicity with certain medications, such as:.
Let's face it - drug interactions are complicated and numerous, so have your medications, even herbals and OTCs, screened by your pharmacist to review for black cohosh drug interactions. CoenzymeQ10 , also known as ubiquinone or CoQ10, is found naturally in the heart, kidney, liver and pancrease, but aging and smoking can deplete these natural stores.
CoQ10 is promoted to help heart damage caused by certain cancer medicines and for breast cancer, gum disease, or muscular dystrophy, although robust studies confirming these uses are lacking. However, use of CoQ10 with anticoagulant drugs like warfarin may decrease the blood thinning effects of the anticoagulant and increase the risk for a clot. If you are considering the use of any supplement, always check with your doctor first.
And if you take a blood thinner, check with your doctor before starting CoQ You may need to have your blood clotting tests checked more frequently and may need a change in your anticoagulant dose. Even the simple cranberry can have drug interactions. Cranberries are a fruit chock full of vitamin C, and some people drink cranberry juice to help prevent urinary tract infections UTI. Although data is conflicting , some studies have shown cranberry can reduce recurrent UTIs in pregnant women, the elderly and hospitalized patients; but it is not helpful to cure a UTI.
Cranberry may exert an increased effect on blood thinners anticoagulants like warfarin and lead to bruising or bleeding. If you take an oral blood thinner, check with your doctor before consuming unusual amounts of cranberry or cranberry juice. You may need to have your International Normalized Ratio INR or other blood clotting lab test checked more frequently.
Echinacea has been used to stimulate the immune system, and is most commonly used in the treatment of the common cold. Most echinacea drug interactions are minor.
Echinacea might slow the breakdown metabolism of caffeine in your body, and could lead to side effects like jitteriness, headache, or insomnia. Echinacea may also change how the body metabolizes many drugs that go through the liver.
These are somewhat complicated interactions that can lead to side effects or reduced effectiveness of your medicine, so always check with your pharmacist. Evening primrose is a flowering plant known by other names such as Oenothera biennis, scabish, or king's cureall.
Evening primrose oil provides fatty acids used by the body for growth. Evening primrose oil contains gammalinoleic acid that may slow blood clotting and increase the likelihood of brusing or bleeding. If you take drugs or herbs that may have blood thinner effects, check with your health care provider before using evening primrose oil.
Use of evening primrose oil may increase the risk for seizures if you take anti-seizure medications or phenothiazine drugs. You can check for other evening primrose oil drug interactions here. Valerian has been used to treat insomnia and anxiety, although evidence is conflicting. Germany's Commission E, the authorities that evaluate the use of herbal products in Germany, has approved valerian as an effective mild sedative.
There are over possible drug interactions with valerian, so a drug interaction screen is important when using valerian. These drugs may increase drowsiness and dizziness while you are taking valerian. Drug interactions with St. John's Wort can be numerous and dangerous. Due to the seriousness of many drug interactions, you should consult with your health care provider before using St. Do not combine St. John's Wort with these medications:. Check with your doctor or pharmacist for a drug interaction screen with St.
John's Wort if you also take prescription, OTC, vitamin or other herbal medications. Use of saw palmetto is popular for benign prostatic hypertrophy BPH , a noncancerous prostate gland enlargement.
Evidence suggests that saw palmetto may be effective for mild-to-moderate BPH, but always ask your doctor for advice about this product. Side effects of St.
John's wort include dry mouth, dizziness and confusion. Phototoxicity manifested as elevated, itching, erythematous lesions has also been reported in association with the use of St. In one case report, 18 a year-old woman developed stinging pain on sun-exposed areas after four weeks of self-treatment with ground St. Her pain was worsened by cold, minimal mechanical stimuli and sun exposure.
After she stopped taking St. John's wort, her symptoms resolved gradually over two months. The patient's symptoms were attributed to demyelination of cutaneous axons caused by photoactivated hypericins. Ephedrine and related alkaloids are the pharmacologically active moieties of the extract of Ephedra a genus of shrubs. The extract of some species also contains pseudoephedrine.
Ephedrine-containing products are also marketed as decongestants, bronchodilators and stimulants. In the past few years, the FDA has investigated more than reports of adverse reactions associated with more than different products that contained or were thought to contain Ephedra alkaloids. Approximately 56 percent of the reported adverse effects occurred in persons younger than 40 years old; about another 25 percent occurred in persons 40 to 49 years of age.
The relatively young age group in which serious cardiovascular events have occurred is of concern. In response to the reports of cardiovascular effects, the FDA has proposed a dosage limit of 8 mg every six hours 24 mg per day for ephedra alkaloids.
The proposed rule also calls for a label advising consumers not to use an ephedrine-containing product for more than seven days and warning that exceeding the recommended dosage may result in heart attack, stroke, seizure or death. The Association of Food and Drug Officials AFDO , which represents state food and health department officials, believes that serious adverse effects to ephedrine-containing products may occur even at a dosage of 24 mg per day.
Ephedra-containing products have also been associated with the development of kidney stones. Ephedrine, pseudoephedrine and metabolites comprised almost percent of a radiolucent stone removed from a year-old male body builder who took up to 12 Pro-Lift tablets daily.
Each tablet was found to contain approximately 10 mg of ephedrine. Information from a large kidney stone database shows that this is not an isolated incident; over ephedrine-containing kidney stones were identified from January to June It is not known how many of these stones were associated with the use of herbal ephedrine-containing products.
The risks of using ephedrine-containing supplements appear to outweigh the benefits. Consequently, patients should be advised not to use these products if they are sensitive to the effects of sympathomimetic agents. Concomitant use of ephedrine-containing products and caffeine or other stimulants should also be discouraged. Little scientific evidence shows that ginseng is effective for any purpose. Nonetheless, this herb has been purported to strengthen normal body functions, increase resistance to stress and improve sexual function.
A year-old man with a mechanical heart valve who was taking warfarin to prevent thromboembolic events experienced a decline in International Normalized Ratio INR from 3. His other medications included diltiazem Cardizem , nitroglycerin and salsalate Disalcid ; he had been taking all three drugs for at least three years.
The patient denied changes in drug therapy or diet, and he stated that he was not taking dietary supplements other than the ginseng product.
Two weeks after he discontinued use of the ginseng product, his INR was 3. Because of the risks associated with a decreased INR, the patient was not rechallenged with ginseng.
Until studies or additional case reports can verify the interaction between ginseng and warfarin, it would be prudent to closely monitor patients on warfarin who begin taking dietary supplements that contain this herb.
A possible mechanism for this interaction is not yet known. Kava is an herbal sedative with purported antianxiety or calming effects. In one case series involving four patients, 29 kava was associated with extrapyramidal effects at dosages of to mg per day.
Symptoms occurred 90 minutes after one patient took a single mg dose, four hours after one patient took a single mg dose, four days after one patient began taking mg three times daily, and 10 days after one patient began taking mg twice daily. The extrapyramidal side effects included oral and lingual dyskinesia, torticollis, painful twisting movements of the trunk, oculogyric crisis and exacerbation of Parkinson's disease.
Kava has also been shown to have additive effects with central nervous system depressants. A patient who was taking alprazolam Xanax , cimetidine Tagamet and terazosin Hytrin became lethargic and disoriented after ingesting kava. Kava should not be used with benzodiazepines, barbiturates, antipsychotics and alcohol. In addition, patients with Parkinson's disease should be discouraged from using kava products. Kava dermopathy has been reported with the use of kava as a traditional South Pacific beverage.
Recently, two cases associated with use of commercially available kava preparations were reported. Erythematous, infiltrated plaques then developed on his face, chest and back.
A similar case involved a year-old woman who presented with papules and plaques on her face, arms, back and chest after taking a kava extract for three weeks. In both cases, biopsy revealed lymphocytic infiltration of the dermis with destruction of the sebaceous glands. Because kava is lipophilic, it was hypothesized that kava can concentrate in sebaceous oils and trigger an immune response, resulting in a drug reaction. Because dietary supplements are becoming increasingly popular, physicians need to ask questions about the use of herbal products as part of the medication history Table 3.
Even though herbal products are available without a prescription, medical guidance is necessary because of the adverse effects of these products and the potential for drug interactions. Consequently, physicians need to stay abreast of trends in dietary supplement use, with the realization that for most supplements the adverse effects and potential for drug interactions are not well characterized. If so, are you taking any prescription or nonprescription medications for the same purpose as the herbal product?
Objective information about herbal products can be obtained in publications such as Alternative Medicine Alert and Review of Natural Products Already a member or subscriber? She earned her pharmacy degree at West Virginia University School of Pharmacy and completed a hospital pharmacy practice residency at West Virginia University Hospitals. Address correspondence to Melanie Johns Cupp, Pharm.
Box , Morgantown, WV Reprints are not available from the author. Unconventional medicine in the United States. Prevalence, costs, and patterns of use. N Engl J Med. Dietary Supplement Health and Education Act of Rosenblatt M, Mindel J. The general sense of the situation among Chinese doctors has been that herbs reduce the side effects of drugs and help them to perform their function better; in turn, drugs will make an herb formula work more strongly and quickly.
Together, herbs and drugs may produce a more desirable result than either taken alone. As an outcome of working within this scenario, little attention has been paid to adverse herb-drug interactions.
The Chinese culture is one in which herbs were a dominant medical therapy during the 20th Century, and drugs were a relatively recent addition to the medical field. The situation was different in the West. Herbs had been almost entirely replaced by drugs during the 20 th Century, and were later reintroduced once drugs had become a dominant feature of modern health care. In the West, the replacement of herbs by drugs took place over a period of many decades during which there was a prevailing attitude that drugs were more reliable than herbs.
The re-introduction of herbs brings with it suspicions and concerns about their unreliability and the lack of adequate knowledge about them. Today, doctors and pharmacists are provided courses and educational materials outlining potential problems with herbs that their patients may be using. The matter of herb-drug interactions involves a considerable amount of speculation about what might happen, based on knowledge-which is also quite limited-about drug-drug interactions and food-drug interactions.
An example presentation to doctors is the following chart, produced in and presented by Jerry Cott, a neuropsychopharmacologist:.
This chart first divides interaction concerns into broad subgroups, the main ones being related to pharmacodynamic interactions mostly involved with herbs and drugs yielding similar effects or counteracting one another and pharmacokinetics such as changing the rate of absorption or elimination of a drug.
There are also two specialty groups: Very little information about actual interactions is imbedded in the presentation. There is mention of "xanthines" e.
Under the cardiovascular heading, there is mention of "glycoside-containing. Generally, the field of herbal medicine has been purged of ingredients with cardiac glycosides; there remains a concern that one of the cardiac glycoside-containing herbs will find its way into a product by mistake.
Under the heading hematological, there is mention of "coumarin containing," which makes reference to the fact that some herbs contain coumarins which might act along with Warfarin, a coumadin binary coumarin, much more potent than coumarins , or along with other blood thinners.
The table also makes passing mention of tannins an herb component with several health benefits that can bind up drugs in the intestinal tract and make them less available. Under Chinese herbs, there is mention of three issues: Sho Saiko To with interferon in treatment of hepatitis to cause an immune response leading to lung damage; the possible interaction of salvia danshen and Warfarin, leading to excessive blood thinning; and the possible interaction of aristolochic acid and diuretic drugs or others to cause renal failure.
Other than these few specific examples all of which have been addressed by previous START articles , the chart outlines areas of concern, but not necessarily known problems. Due to the paucity of actual reports of herb-drug interactions, lists of herb-drug interactions are usually padded with other information, such as reports of simple adverse reactions not involving interactions.
A table provided to pharmacists of this nature is shown here; it is by Pharmacists Planning Service, Inc. Echinacea boosts the immune system and helps fight colds and flu. Echinacea may cause inflammation of the liver if used with certain other medications, such as anabolic steroids, methotrexate or others. Ephedra is also called Ma-Huang. It is used in many over-the-counter diet aids as an appetite suppressant. It is also used for asthma or bronchitis.
Ephedra may interact with certain antidepressant medications or certain high blood pressure medications to cause dangerous elevation in blood pressure or heart rate. It could cause death in certain individuals. Feverfew is used to ward offf migraine headaches and for arthritis, rheumatic disease and allergies.
Feverfew may increase bleeding, especially in patients already taking certain anti-clotting medications. Garlic is used for lowering blood cholesterol, triglyceride levels and blood pressure. Garlic may increase bleeding, especially in patients already taking certain anti-clotting medications.
Ginger may increase bleeding, especially in patients already taking certain anti-clotting medications. Ginkgo, also called ginkgo biloba, is used for increasing blood circulation and oxygenation and for improving memory and mental alertness. Ginkgo may increase bleeding, especially in patients already taking certain anti-clotting medications. Ginseng may cause decreased effectiveness of certain anti-clotting medications.
Persons using ginseng see increased heart rate or high blood pressure. It may cause bleeding in women after menopause. Goldenseal is used aas a mild laxative and also reduces inflammation. Kava-kava is used for nervousness, anxiety or restlessness; it is also a muscle relaxant. It may increase the risk of suicide for people with certain types of depression. Certain licorice compounds may cause high blood pressure, swelling or electrolyte imbalances.
Saw Palmetto is used for enlarged prostate and urinary inflammations. People using saw palmetto may see effects with other hormone therapies. John's Wort is used for mild to moderate depression or anxiety and sleep disorders. John's Wort may prolong the effect of certain anesthetic agents. Valerian is used as a mild sedative or sleep-aid. It is also a muscle relaxant. Valerian may increase the effects of certain anti-seizure medications or prolong the effects of certain anesthetic agents.
References to what the herbs "may" do when combined with certain drug groups, e. For example, when one wishes to demonstrate that valerian, used traditionally for seizures and for analgesic effects, is likely to accomplish what has been claimed, laboratory animal studies are conducted. A standard procedure is to test the herb extract alone and to also test it with drugs that cause the same effect.
If the drug effect is increased or prolonged by the herb, it is implied that the herb has a similar effect, even though it may have a different mechanism. Thus, a study intended to demonstrate that a traditional claim for an herb is true turns out to be a source of worry about herb-drug interactions.
However, the amount of herb used in the pharmacology experiments of this type is often far higher than the amount normally used in clinical practice; the likelihood of herb-drug interactions occurring with normal use of the herb may be minimal. Still, if one wishes to consider possible herb-drug interactions under a variety of scenarios, including excessive use of the herb and use of the herb by individuals who are more sensitive to the possible interaction, then such data must be included.
When published reports alluding to adverse herb reactions but not interactions and to pharmacology studies only are eliminated, one is left with few instances of reported herb-drug interactions. This is likely due to the low dose of any individual herb component usually consumed and the simple absence of significant interaction at any reasonable dose.
To help illustrate the low frequency of clinical reports, the following abstract of a recent publication will be informative:. Drug-herb interaction among commonly used conventional medicines: The objective of the review was to consolidate the clinical and pharmacologic aspects of drug-herb interactions to develop a compendium of information to provide prescribers with a measure of the risk of interactions, a description of the clinical consequences, and an assessment of the quality i.
A variety of electronic databases and hand-searched references were used to identify documentation of interactions between herbal products and drugs from the most commonly used therapeutic classes. One hundred sixty-two citations were identified. Only 22 citations met the inclusion criteria. The remaining interaction pairs reflected theoretic reasoning in the absence of clinical data.
Most interactions were pharmacokinetic, with most actually or theoretically affecting the metabolism of the affected product by way of the cytochrome P enzymes.
In this review, Warfarin was the most common drug and St. John's Wort was the most common herbal product reported in drug-herb interactions. To create a comprehensive and valid list of herb-drug interactions would require a substantial increase in research activities in this area.
Improvements in the quality of methodology used are also necessary. Put simply, there were very few well-supported interactions detected: Not surprisingly, the main drug of concern is Warfarin, which displays substantial sensitivity to interactions with foods and drugs, and which is very widely used giving more opportunities to note interactions , while the primary herb involved is St.
Herbal Remedies: Adverse Effects and Drug Interactions
Because of this, herbal supplements can have drug interactions, even with each . How Should I Handle Possible Herbal-Drug Interactions?. Among several factors, herbal drug interactions (HDI) are one of the major concerns. There are various kinds of potential interactions that have the possibility of It could also cause the drugs to be ineffective to treat the condition because. Unlike conventional drugs, herbal products are not regulated for purity effects should be cautioned about potential interactions with ginkgo.