Surveillance of suspected adverse reactions to herbal products used as laxatives

To describe and evaluate spontaneous reports of suspected adverse reactions (ARs) associated with herbal laxatives received by the Italian Medicines Agency and the Italian National Institute of Health between April 2002 and January 2011.

Spontaneous reports of suspected ARs were individually analyzed by a multidisciplinary group of experts, and a causality assessment was performed.

Twenty-six reactions were reported during the study period. Of these, eight were associated with herbal medicinal products and 18 were related to herbal food supplements. Almost 80% of the reports on ARs involved women. The ARs, classified by System Organ Class, were associated with gastrointestinal, skin and subcutaneous tissue, and hepatobiliary disorders. Fifty percent of the reactions were serious, with the patients requiring hospitalization; of these, one was life-threatening. Most of the herbal remedies associated with the reported ARs contained liquorice, dandelion, and/or plants containing anthraquinones. Possible causes of the ARs were long-term use, idiosyncratic reactions or hypersensitivity, and interaction with other treatments. All of these factors and the presence of a large number of components in the same product increased the unpredictability of the final effect.

The total number of 26 ARs recorded in 8 years is limited; however, the an under-reporting effect cannot be excluded. Moreover, taking into account the seriousness of the reported ARs, the low number of reports does not represent a guarantee of safety. To reduce the risk of an adverse outcome, herbal laxatives should be used only over the short term.