With an estimated 40-50 percent of adult Americans using herbal dietary supplements, it is inevitable that some of these pharmacologically active herbal products will interact with the over-the-counter or prescription drugs people are using. The interactions could either lead to medical problems or in some cases might even interact in a beneficial way. In the past, there has not been a great deal of information published in this area of increasing concern to health professionals, consumers, members of industry, and even regulators. In essence, the development of reliable databases on herb-drug interactions is in its relative infancy and represents a relatively new frontier in herbal research.
This book is a welcomed revision and improvement over the edition published in 1997. The second edition includes more botanicals and has greatly improved upon the previous edition by providing primary references for each of the interactions mentioned.
Current information available on herb-drug interactions has relied on the German Commission E monographs, the ESCOP (European Scientific Cooperative on Phytotherapy) monographs, and other authoritative primary and secondary sources. Interactions noted by Commission E or ESCOP, for example, sometimes are based on known interactions, and in some cases, theoretical interactions based on suspected activities of primary active compounds in botanicals, interacting with a presumed interaction with the particular conventional drug. However, a cogent interactive database has been lacking. Dr. Brinker, a research-oriented doctor of naturopathic medicine, has provided an invaluable service to the herb research community by developing a hierarchy of evidence and ascribing this hierarchy to each cited reference for each particular interaction. The book includes approximately 207 herbs total, including those with contraindications only, 79 herbs with interactions, and herb-drag interactions.
The author has rated the interactions according to the following hierarchy:
1) in vitro -- laboratory finding with cell or tissue samples from animals or humans
2) in animals (types listed) -- laboratory tests using live animals in various models of administering the herb or herbal component(s)
3) speculative -- using indirect evidence such as extrapolation of empirical effects or in vitro research, animal studies, or case reports to infer probable or potential effects in humans
4) empirical -- traditional knowledge or belief based on experience from extensive use
5) human case reports -- published individual responses to using herbs
6) human studies -- published research done on healthy individuals
7) human clinical studies -- published research from therapeutic trials on patients being treated for a condition
In addition, in each cited reference the author includes whether the substances were administered through injection by mouth, or subcutaneously, l.m., i.p., i.v. -- all of which may have a direct bearing on the appropriate interpretation of the information.
The book is divided into five parts:
1) the Herb Contraindications and Drug Interactions of about 118 pages.
2) Appendix A, "Herbs To Be Used With Caution," in which the author creates reasons for caution: potential allergic response, potential photosynthesizing effects, local irritant effects when fresh, acute inflammation of the urinary tract, gastrointestinal irritation, hypothyroid conditions, or euthyroid goiter.
3) Appendix B, "Herb-Drug Interactions," includes herbs that modify the intestinal absorption of medicine, potentiate cardiotonic medicines, potentiate sedative or tranquilizing medicines, modify blood sugar in insulin-independent diabetics, modify the effects of prothrombopenic anticoagulants, and that concern incompatible GI tract medications.
4) Appendix C, "Herbs Contraindicated for Mothers and Children," includes herbs to avoid during pregnancy, while breastfeeding, and in children.
5) Appendix D, "Vitamin/Mineral/Drug Interactions," includes drug interactions with vitamin supplements vs. herbs/foods and drug interactions with mineral supplements vs. herbs/foods.
The book contains 394 references in the text. As evidenced by the progression from the first edition, a book like this is a work in progress, One can safely assume that the author will publish a third edition within the next year or so in which additional data gained from the literature will be accumulated and systematically presented. Dr. Brinker has done a great service to the entire herbal community by providing this data -- the first publication of its type in an area of increasing interest and importance.
Article copyright American Botanical Council.
By Mark Blumenthal