AYLMER (PasseportSanté.net) February 13, 2006 – Worrying, the interactions between natural health products and drugs? The only certainty is that currently, we know very little about the real risks.
At least that is the opinion of the experts who participated in the International Symposium on Interactions between Drugs, Foods and Natural Health Products.1, an initiative of the Canadian Department of Health.
“The use of natural health products is on the rise all over the world. Their possible interactions with drugs constitute an extremely complex problem and the solution will not be simple ”, immediately launched the renowned Edzard Ernst, holder of the Laing Chair in Complementary Medicine, attached to the University of Exeter in Great Britain. Brittany.
The potential risks do exist, according to Edzard Ernst, especially since, unlike drugs, plants contain several different active ingredients and their mechanisms of action are little or not known. Also, the quality of products prepared from medicinal plants is variable.
Based on scientific data, NHPs can have an impact on drug absorption, elimination, metabolism, and may increase or inhibit their effects. In addition, in many countries including Canada, the forms currently completed by health professionals to report an adverse reaction or drug interaction do not include a section for NHPs.
Patients, doctors: ostrich syndrome?
According to several surveys referred to by various speakers, many patients take both drugs and NHPs, especially the elderly and those with chronic illnesses. For example, a survey of 1,360 UK patients taking the blood thinner warfarin found that 19% were also taking at least one herbal supplement.2. Of these patients, 9% were at potential risk of interaction. However, the vast majority of those questioned had not informed their doctor that they were taking NHPs.
“Patients are unaware that there is a risk and do not inform their health care professional about their consumption of natural health products,” said Edzard Ernst on the basis of other surveys3.4. And unfortunately, he added, their doctors don’t do better: They don’t ask their patients questions and don’t know that NHPs can interact with the drugs they prescribe.5! “
Scientific data difficult to interpret
Even knowledgeable experts agree that the scientific literature on drug-NHP interactions leaves a lot to be desired. This field of research is very recent compared to that of interactions between drugs. For example, the observation reports sent by health professionals to the authorities (case reports) are mostly incomplete. “According to a summary of 108 of these reports, 69% were unusable and only 13% were well documented6. We need to develop publication guidelines to improve the quality of this data, ”said Edzard Ernst.
Data from laboratory (in vitro) experiments and animal studies are also listed. But these results remain theoretical as long as they have not been reproduced in humans. “Clinical trials that specifically focus on interactions between drugs and NHPs are still too rare,” said Edzard Ernst, summarizing a recent summary which analyzed 47 of them.7. Among the 19 products examined, the researchers noted potentially risky interactions in the cases of St. John’s Wort, garlic and ginseng and certain designer drugs.
According to other sources, ginkgo biloba, echinacea and kava are also natural health products to watch for possible interactions.8. “The current reality is that we know very little about the real risks,” concluded Edzard Ernst.
Another point that complicates the assessment of the real risk, in trials conducted in humans, healthy people are recruited. Result: this does not give a realistic picture of the interactions that could affect sick or debilitated people.
Is there cause for alarm?
The potential risk is great, but are the interactions serious? According to a survey of 458 US veterans, 43% were taking a herbal product. Of the products they consumed, 45% presented a risk of interaction, but 94% of these interactions were not dangerous3. “Which still leaves us with 6% of potentially serious interactions,” said Edzard Ernst.
Even low, these risks cannot be neglected, especially since, just like in the case of drugs, the undesirable effects of these interactions are not always reported.
“Although few serious interactions occur between plants and drugs,” added Mark Blumenthal, editor of the journal. Herbalgram and Executive Director of the American Botanical Council10, consumers want to know more about it. “
However, according to him, the main sources of information for consumers are labels, which say very little, and the media, which sensationalize based on theoretical speculation, poorly documented reports or even erroneous data. “It’s double standards, double measures,” he exclaimed. Controlled clinical trials are rightly required to prove the efficacy of herbs, but often one relies on poorly documented anecdotal reports or speculative data to conclude that an interaction exists. “In a very well documented presentation, Mark Blumenthal flayed the American magazine in passing. Consumer Reports which, in May 2004, included skullcap, among 12 NHPs considered dangerous, while this plant is quite safe11.
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Some figures concerning the regulation on NHPs
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Source: World Health Organization, 2005.
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For more news on the International Symposium on Drug, Food and Natural Health Product Interactions, see our Dossier index. |
Françoise Ruby – PasseportSanté.net
1. This event, entitled Health Canada International Symposium on Interactions between Drugs, Foods and Natural Health Products, was held on February 9 and 10, 2006. It brought together more than 250 people from the health field. , the medicinal plants industry, as well as researchers, representatives of various branches of Health Canada and some consumer groups.
2. Smith L, Ernst E, PaulEwings, Myers P, Smith C. Co-ingestion of herbal medicines and warfarin, Br J Gen Pract, 2004 Jun; 54 (503): 439-41. Erratum in: Br J Gen Pract. 2004 Jul; 54 (504): 547.
3. Peng CC, Glassman PA, Trilli LE, Hayes-Hunter J, Good CB. Incidence and severity of potential drug-dietary supplement interactions in primary care patients: an exploratory study of 2 outpatient practices, Arch Intern Med, 2004 Mar 22; 164 (6): 630-6.
4. Giveon SM, Liberman N, Klang S, Kahan E. Are people who use “natural drugs” aware of their potentially harmful side effects and reporting to family physician?Patient Educ Couns, 2004 Apr; 53 (1): 5-11.
5. Clement YN, Williams AF, Khan K, et al. A gap between acceptance and knowledge of herbal remedies by physicians: the need for educational intervention, BMC Complement Altern Med, 2005 Nov 18; 5:20.
6. Fugh-Berman A, Ernst E. Herb-drug interactions: review and assessment of report reliability, Br J Clin Pharmacol, 2001 Nov; 52 (5): 587-95, Review. Erratum in: Br J Clin Pharmacol 2002 Apr; 53 (4): 449P.
7. Mills E, Wu P, Johnston BC, Gallicano K, Clarke M, Guyatt G. Natural health product-drug interactions: a systematic review of clinical trials, Ther Drug Monit, 2005 Oct; 27 (5): 549-57.
8. Sparreboom A, Cox MC, Acharya MR, Figg WD. Herbal remedies in the United States: potential adverse interactions with anticancer agents, J Clin Oncol, 2004 Jun 15; 22 (12): 2489-503. Review.
10. The American Botanical Council (ABC), founded by M. Blumenthal in 1988, is a non-profit organization dedicated to the dissemination of accurate and reliable information on medicinal plants. HerbalGram is a quarterly review: http://herbalgram.com/
11. Dangerous supplements still at large, Consumer report, May 2004. www.consumerreports.org
