Which herbs might have specific importance in the hospital setting? This question was answered to some degree by researchers at the University of Chicago in 2001.14 The authors reviewed the literature on commonly used herbal medications in the context of the perioperative period and attempted to provide rationale strategies for managing their preoperative use. They identified echinacea, ephedra, garlic, ginkgo, ginseng, kava, St. John’s wort, and valerian as commonly used herbal medications that could pose a concern during the perioperative period.
Direct effects include bleeding from garlic, ginkgo, and ginseng; cardiovascular instability from ephedra; and hypoglycemia from ginseng. Pharmacodynamic herb-drug interactions include potentiation of the sedative effects of anesthetic by kava and valerian. Pharmacokinetic herb-drug interactions include increased metabolism of many drugs used in the perioperative period by St. John’s wort. (The findings are outlined in “Table 1. Clinically Important Effects and Perioperative Concerns of Eight Herbal Medicines and Recommendations for Discontinuation of Use Before Surgery,” p. 16.)
These authors concluded, “during the preoperative evaluation, physicians should explicitly elicit and document a history of herbal medication use. Physicians should be familiar with the potential perioperative effects of the commonly used herbal medications to prevent, recognize, and treat potentially serious problems associated with their use and discontinuation.”
However, it is quite clear that the numbers of herbs that patients can encounter seem almost limitless, and there is no way for any clinician to maintain currency with every potential toxicity or other adverse event. Because of the phenomenon of new herbs becoming popular almost on a monthly basis, the use of textbooks to assist the hospital clinician in identifying potentially toxic herbs or drug–herb interactions has limited utility.
For the most part, databases that maintain greater currency of such reports are most helpful. Some of this information can be found in nonproprietary sites (see “Table 2. Helpful Herbal Databases,” to right), whereas others require a subscription. In the latter category, Natural Medicines Comprehensive Database (www.naturaldatabase.com) is a helpful and extremely comprehensive resource. It is laid out in a systematic fashion that makes it easy to identify an herb of interest, discover if there are potential adverse effects, and also provide patient handout information to patients.
Some of the bloom is off the rose in terms of enthusiasm for dietary supplements and herbs as a panacea for all human ills. Increasingly, consumers are becoming savvy with regard to challenges related to quality of products including contamination and lack of standardization. In addition, the common mythologies that “herbs are natural and therefore safe” or that “if two doses of an herb are good, 10 must be better” are slowly becoming recognized as the dangerous platitudes that they are. A more rationale approach to herbal use is slowly emerging.
With a more informed public and better resources for physicians to counsel patients and consumers, it is possible that we will see beneficial dietary supplements and herbs assume a helpful role in managing common problems. For example, valerian may be of significant benefit in helping restructure sleep patterns in patients with insomnia (possibly with fewer side effects than benzodiazepines and less expense than some of the newer hypnotics). Still, long-term studies are generally lacking, so final determination of the role of valerian in the physician’s armamentarium await such studies.
At the Mayo Clinic, many such studies are under way. The use of valerian as a sleep aid for patients undergoing chemotherapy is nearing completion. Another study looking at the role of American ginseng (Panax quinquefolius) as a treatment for cancer-related fatigue has just gotten under way. As these and dozens of similar studies at research institutions across the country are completed, the missing pieces in the herb story will begin to be filled in.