Stockley's Herbal Medicines Interactions: A Guide to the Interactions of Herbal Medicines. Second edition

Abstract

Four years have elapsed since the publication of the first edition of Stockley's Herbal Medicines Interactions (2009). The second edition continues the standard established in the first, “providing expertly assessed, constructive, practical advice on the potential interactions of herbal medicines…with conventional drugs” (p. vii). Acknowledging that health care professionals may not be as knowledgeable about herbal medicines as is needed to provide adequate advice to patients, the primary intention of the book is that it be easy to use to provide current, evidence-based information about herbal–conventional drug interactions in the clinical setting. The editors have defined “herbal medicine” to include traditional herbals, nutraceuticals, dietary supplements, and some food items. The editors explain that the herbal medicines included in the monographs “have been chosen on the basis of their popularity and/or because they have interaction reports associated with them” (p. xi). The second edition includes nearly 200 monographs, 40 more than in the first edition. All previously included monographs have been revised and revalidated. Stockley's Herbal Medicines Interactions uses “interactions monographs” to detail herbal–conventional drug interactions. Nearly 800 interactions monographs are included in the appropriate herbal medicine monographs. The treatise is arranged alphabetically by the most common name of the herbal medicine, with thumb-index markings on the pages, making navigation of the book very easy. Each monograph includes synonyms, pharmacopoeias, constituents, uses and indications, pharmacokinetics, and an interactions overview. Where interactions with conventional drugs have been reported, the interactions monographs include clinical evidence detailing the interaction; experimental evidence, noting if it is from animal or in vitro studies; the mechanism of interaction; the importance and management of the interaction; and references to the supporting evidence. The second edition has been revised to include an index of page numbers for drug interactions in the interactions monographs. This is particularly helpful for herbals that have a large number of interactions, such as St. John's wort, which has fifty-one interactions listed. The interactions monographs include five levels of hazard or severity rating symbols: interactions that have life-threatening outcomes, interactions that have a significant hazard requiring dosage adjustment or close monitoring, interactions that have potentially hazardous outcomes that are poorly documented, interactions where there is doubt about the outcome of concurrent use, and interactions that are not considered to be clinically significant (pp. ix–x). It would be a helpful design feature to have a legend for the hazard rating symbols included for easier reference throughout the text, rather than just in the prefatory explanation. The comprehensive index includes cross-referencing by scientific names, common names and synonyms, drug names, constituents, and broad terms (such as “alcoholic beverages”). The layout of the index makes it clear and easy to read. The nomenclature is British, with American and other international terms added, where helpful. For example, “acetaminophen” is cross-referenced to “paracetamol.” There does seem to be some inconsistency with page numbers references in the index. The listing for “cannabis,” for example, includes the page number for the monograph, whereas the listing for “aloe vera” only includes page numbers for the associated interactions monographs. Stockley's Herbal Medicines Interactions includes rich material in an introductory chapter, “General Considerations.” The information included in sections such as “Who Uses Herbal Medicines?,” “Herbal Medicine Use in Specific Population Groups,” “Mechanisms of Drug Interactions,” and “Pharmacodynamic Interactions” provides concise topic reviews. Also included in the introduction are tables of drug and herbal metabolism by cytochrome P450 isoenzymes. As the introductory content might well be used by readers seeking a quick, global overview of the topic, it is unfortunate that the editors provided minimal updating of the statistical and journal references for these sections. Much of this material has been included, verbatim, from the first edition, referring to articles from 2006 and 2007 to describe, for example, herbal medicine use in weight-loss programs or use of herbals by the elderly. The second edition has been updated, throughout, with information about use of herbal medicines with HIV infection. Statistical information on use of herbal medicine by patients with HIV is now included in the “General Considerations” chapter, and interaction monographs have been updated with HIV drug interactions information. It is difficult to evaluate the ultimate authority of this title when one acknowledges that “herbal medicine” is, in actuality, a fuzzy science. Comparing Stockley's Herbal Medicines Interactions with other well-regarded herbal medicine sources (Micromedex, Herbal Medicine Expanded Commission E Monographs, Meyler's Side Effects of Herbal Medicines) yields mixed results as there is little standardization to the herbals included in each title, to the content provided, or to the drug interactions described for any given herbal. Each title has a unique contribution to make to the literature of herbal medicine. The strength of Stockley's Herbal Medicines Interactions is that the focus is herbal–conventional drug interactions. It is not the source to use to determine side effects, dosage, or administration of herbal medicines. It is designed for ease of use in a busy clinical setting with herbal–drug interaction assessments and recommendations based on well-documented evidence from clinical trials, animal, and in vitro studies. Stockley's Herbal Medicines Interactions would be a valuable addition to collections strong in pharmacology, alternative medicine, family practice, or internal medicine.