The use of plants for healing purposes and the knowledge required for their use (pharmacognosy) predates written human history and forms the origin of much of modern medicine. Many conventional drugs originate from plant sources; in fact, a century ago, of the few effective drugs that were available, most were plant-based. In 1870, the U.S. Pharmacopeia listed 636 herbal entries; the 2018 edition listed 26 herbal entries (U.S. Pharmacopeial Convention, 2018). Although some of these original herbal entries were found to be unsafe, most were replaced by pharmaceuticals derived from the original botanical medicines. Examples include aspirin (from willow bark), digoxin (from foxglove), quinine (from cinchona bark), and morphine (from the opium poppy). The development of drugs from plants continues, with drug companies being engaged in large-scale pharmacological screening of herbal substances.

In the United States and Europe, however, over-the-counter natural herb products constitute a rapidly growing market, having joined prescription and over-the-counter medicines that were originally derived from herbs. Interest in herbal medicine has been facilitated by multiple factors, including the perception that pharmaceutical medications are expensive, overprescribed, and often dangerous. Alternatively, herbal medicines are often perceived as being “natural,” and therefore safe.

Herbal medicines now fall into the category of complementary and alternative medicines (CAMs). Herbal supplements are receiving increasing exposure through national media, in lay journals, and more recently in the scientific press. Although the growth of the herbal medicine industry in the United States can probably not continue indefinitely at its current accelerated pace, there is little indication of any major slowing. Therefore, many patients will continue to use herbal medications. In fact, one survey conducted in the United States found that an estimated 12.3 million adults (5.4% of the population) used alternative therapies as a substitute for costly prescription medications.

With the increasing popularity of CAMs, a new issue has arisen: herbal-drug interactions, of which oral healthcare professionals (OHCPs) must be aware. A survey of patients with heart disease, diabetes, psychiatric disorders, and/or hypertension found that 79% were taking supplements concurrently with prescription medications. Among those with cardiac disease, 20% reported regular use of herbals. About 16% of patients with diabetes and 16% of patients with psychiatric disorders reported regular use of CAMs. The results of this survey underscore the prevalence of herbal supplement use and the potential for herbal-drug interaction. Thus, the OHCP needs to be increasingly aware not only of these products’ effects and advantageous synergies, but also of their side effects and possible or probable adverse drug reactions.

• Describe the prevalence and risk for interactions involving herbal medications.
• List the herbal medications and drugs of greatest concern to dental professionals.
• Describe the ways in which levels of risk for herbal-drug interactions are evaluated.
• Identify the medical and dental implications for drug interactions with specific herbal medications.
• Discuss the special considerations of herbal-drug interactions for pregnant or breastfeeding dental patients.

The speaker declares that neither he nor any member of his family has a financial arrangement or affiliation with any corporate offering financial support of grant monies for this CE program. Although commercially available products may be discussed, no financial arrangements exist between those companies and the speaker.