Problematics of Reporting Interaction of Herbal Products

Interaction of herbal products and nutritional supplements are more problematic that those related to the conventional medicinal products. This may be attributed to the significant nomenclature confusion of medicinal herbs despite that fact that their botanical classification has been established for the vast majority of these herbs. This problem is further compounded by the numerous common names used in different cultures and countries throughout the Globe.

The 5th Edition of the Natural Medicines compendium offers a good example to demonstrate the aforementioned assumption. This compendium consists of about 1,037 monographs of medicinal herbs and nutritional supplements. The corresponding number of herbs’ common names / synonyms listed in this reference website approximates 26,000 items.

The problem of accessing Drug-Herb or Herb-Herb interactions is further accentuated by the realization that the majority of herbal products are presented with too many active ingredients, with some containing more than four or even five dozens of herbs and/or other nutritional supplements. This renders the detection of their likely interactions with concurrently administered medications almost an impossible task for clinical practitioners.

Nomenclature of medicinal herbs poses a more serious problem due to the fact that some commonly used names (synonyms) are attributed to more than one botanical or scientific name. This state-of-affair could never occur for conventional drug substances since too many synonyms are usually associated with one officially approved name. For such drugs, a reversal of this situation is out of question.

In a limited example, monographs of five different herbs, with nine synonyms, have been examined to assess their reporting interactions consistency. Results of this exercise are summarized the table provided hereunder. While emphasizing that these herbs were selected at random, it could be readily demonstrated that more than 2,000 such cases exist.

This diagram presents the number of interaction reports for fourteen herbs with other drugs. Noteworthy, these interactions were independently reported in different monographs of either the official herb name or its corresponding synonym in the Natural Medicines compendium. The implication of this state-of-affairs is self-evident. For example, the administration of Abscess Root, with any other drug, is quite safe as indicated by the absence of any interaction in its own monograph, despite the fact that twelve significant interactions are reported for the very herb under the monograph of its synonym, Lily-of-the Valley. In addition, some of the names provided in the above table (Aron’s Rod, Abscess Root and Baggar Weed) are not identified in the general index of Natural Medicines textbook.

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