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Harriet S.MeyerMD, Contributing EditorDavidMorseMS, Journal Review EditorRobertHoganMD, adviser for new media
This superb book subjects 964 natural medicines to current standards of scientific scrutiny. The editors' strict, evidence-based grading system allows them to rate the performance of such remedies for their various indications. Only 46 are considered effective and 72 likely effective. Efficacy is supported by at least two randomized, prospective, controlled, adequately large human studies that give positive results for clinically relevant end-points plus publication in an established refereed journal. The rest of the medicines descend a therapeutic hierarchy: 333 possibly effective, 46 possibly ineffective, 61 likely ineffective, 6 ineffective, and 538 unclassifiable owing to insufficient reliable data (some medicines are given different effectiveness ratings for different indications).
Regarding safety, the editors could objectively rank only 147 natural ingredients as likely safe. Based on the route of administration, the remainder are classified as possibly safe (292), possibly unsafe (118), likely unsafe (131), unsafe (45), and unclassifiable (262).
Overall, the collection indicates that only 15% of natural medicine products have been proved safe and only 11% effective or likely effective for the indications for which they are being used.
The clinically relevant problems associated with phytopharmaceuticals are instructively grouped into (1) interactions between herbs/supplements (eg, the potentially fatal combination of guarana and ephedra), and (2) interactions with drugs (eg, capsicum may exacerbate the cough associated with angiotensin converting enzyme inhibitors; ginkgo can increase blood pressure when used with thiazide diuretics), and (3) interactions with food (wheat bran, for instance, inhibits calcium absorption). St John's wort lowers digoxin levels by about 25% and, within three days of first appearance in the primary literature, new information was posted, namely that St John's wort can interact with cyclosporine, resulting in acute heart transplant rejection and can lower levels of indinavir and possibly other HIV antiretrovirals.
Another clinical curve ball that natural medicines can throw concerns their interaction with lab tests. They can either produce true elevations of serum values (in aminotransferase by coenzyme Q10, in creatinine by creatine, in bilirubin and amylase by lemon grass) or foster misinterpretation of lab results by interference with certain assay methods. Vitamin C, for example, can bring about false elevations in serum aspartate aminotransferase and bilirubin, false decreases in serum lactate dehydrogenase and glucose, and false-negative urine acetaminophen levels and stool guaiac results. By harvesting such information and documenting reports of allergic and other adverse reactions (like the inhibition of oocyte fertilization and alteration of sperm DNA by St John's wort), this book engenders an appropriate respect for natural medicines. As with prescription drugs, the indiscriminate use of natural remedies can cause harm.
The Natural Medicines Comprehensive Database Web page, available at http://www.naturaldatabase.com, is easily navigated and permits subscribers to ask the panel of experts such questions as which specific formulations of Ginkgo biloba were actually used in the clinical trials that established its efficacy for Alzheimer disease and receive a prompt reply. One can also access constantly updated data. Since the December 1999 printed version, for instance, the efficacy of ipriflavone for postmenopausal osteoporosis has been upgraded to likely effective based on six more references. In addition, as new products become popular, they are added to into the Web version, eg, vinpocetine, glossy privet, deanol, Andrographis paniculata, and no doubt others by the time this review is printed.
Because it is probably important that readers know what is not known, whenever available reliable information is insufficient, the authors successfully avoid the flawed explanations found in less authoritative books. Jellin et al point out, for instance, that the single ingredient hypericin does not adequately explain the antidepressant activity of St John's wort, an effect more likely due to hyperforin or possibly other constituents. They also dare to dispute several widely advertised promotional claims, eg, by unearthing dirt about colloidal minerals (which they say are not more bioavailable and may contain lead, arsenic, and other contaminants).
Even when an herb is ineffective, knowing why people use it can be helpful. Thus the monograph on goldenseal discloses that it is promoted to mask the results of lab tests for illicit drug use. With such knowledge, physicians can ask insightful questions. Finally, if a patient asks whether a particular drug will induce nutrient depletion, a handy table has been carefully constructed to address this oft-overblown concern in a rational way.
Natural Medicines Comprehensive Database is highly recommended for all physicians, pharmacists, and others interested in the responsible use of natural medicines sold in North American.
Alternative Medicine: Natural Medicines Comprehensive Database. JAMA. 2000;283(22):2992–2993. doi:10.1001/jama.283.22.2992-JBK0614-2-1
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