What We Don’t Know About Herbal Medicine
While the amount of information and research concerning herbs is increasing, there are still two important matters that have not been clearly defined as to herbs. First, due to the lack of controlled research on herbal remedies, the exact extent of drug-herb interaction is not entirely known. Thus, an herb that a person may be taking in an attempt to prevent liver damage may have a negative interaction with the medication that she is taking to control high blood pressure. For example, licorice—proclaimed to be beneficial in the treatment of viral hepatitis—might cause fluid retention and worsen high blood pressure. Furthermore, licorice may cause a decrease of libido in men, which is a potential side effect of interferon therapy, in addition to being a side effect of many antidepressants which are often used during interferon therapy for hepatitis C. Many herbs may increase or decrease the action of conventional medicines. For example, the herb cannabis sativa (marijuana) has been demonstrated to diminish the effectiveness of interferon and to suppress the immune system. Though potential adverse drug-herb interactions can be looked up in the PDR for Herbal Medicines, this list may be incomplete. An example of such an interaction includes the death of women who was taking St. Johns Wort at the time she underwent anesthesia with the drug Demerol. Due to an adverse drug-herb interaction, this patient experienced fatal cardiac arrest. This also resulted in the filing of a large lawsuit against the herb manufacturer.
Furthermore, the noted side effects of an herb, in general, may be incomplete. This is due to the fact that it can be very difficult to trace side effects to a particular herb. It may take weeks, months, or even years for problems to show up. By that point, people don’t always remember that they have taken an herbal remedy or they have become so accustomed to a particular side effect that they dismiss it. Complicating matters even further, many natural remedies contain dozens of active ingredients depending on exactly how they were prepared by the manufacturer. The composition of these ingredients may vary greatly (even among bottles of the same type of herb). Finally, there are no regulatory laws mandating that the manufacturer or distributor of an herbal preparation report possible adverse reactions of the herb to the FDA or other government agency (see “The Dietary Supplement Health and Education Act of 1994” on pages xx and xx). So, in all likelihood, all the possible drug-herb interactions and other side effects associated with a given herb are not listed in the PDR for Herbal Medicine. This is made clear by reports which appear on a regular basis alerting the public to the danger of an herb that was once thought to be safe. Usually the herb –in-question has caused some unsuspecting consumer to suffer severe, or even fatal, side effects including cancer, kidney failure and liver failure, thereby necessitating the removal of the herb from the market or at least stronger warning labels on the bottle. Examples of such herbs include kava and ephredra respectively.
Second, there is a lack of standardization among herbal products. It is important to be aware that not all parts of the herb contain the active ingredient proclaimed to produce the beneficial effect. For example, one study compared ten different brands of the herb ginseng and found that the active ingredient ginsenoside varied drastically among different brands, although all were essentially similar in their descriptions of ingredients contained in the bottle. In fact, some pills or capsules contained almost none of the active ingredient. A different study found that up to one-quarter of the products on health food store shelves did not contain any of the listed ingredients.
Due to the absence of regulation, it is possible that a totally different herb can be substituted for the one on the label. Furthermore, there have been reports that some herbs have been spiked with steroids, painkillers, tranquilizers, thyroid extracts or other substances to improve their effectiveness. Toxic metals, including lead and arsenic and even powerful heart stimulants (such as digitalis), the blood thinner warfarin, and the diabetic medication glyburide have been discovered mixed in with herbal preparations. And, some herbs have been found to contain dangerous microorganisms, such as staphylococcus aureus, escherichia coli (E. coli), salmonella, and shigella, each of which can make a person quite ill. Of course, the product labels, did not mention the addition of any of these adulterants, and all labels claimed to contain only “natural” ingredients. So how can someone determine whether the contents listed on the label of an herbal product accurately reflect its contents? First, it is important to determine whether the company manufacturing the herbal product is a well-known, legitimate company with a good track record of providing consumers with safe and effective products. Second, a person can request a “certificate of analysis” from the manufacturer concerning a particular herbal product. This ensures that the ingredients listed on the label have been analyzed by a laboratory and are accurately represented on the label. Or a sample of the herbal product can be sent to an herbalist, a nutritionist, or a compound pharmacist, all of whom are capable of performing an analysis of the ingredients contained in the herb. Lastly, a compound pharmacist—a pharmacist who prepares, mixes, assembles, packages, and labels medications from scratch—can prepare an herb in its active form.All contents of this article are Copyright © Melissa Palmer, MD
Melissa Palmer, MD is the author of " Dr. Melissa Palmer's Guide of Hepatitis and Liver Disease". (Published 2004. Penguin Putnam).
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