Le interazioni tra farmaci e fitoterapici attivi sul sistema nervoso centrale= Interactions between drugs and herbal drugs acting on the central nervous system

In the last few years the use of herbal drugs has become very popular. Natural products are commonly used for promoting health and managing diseases, even if there are only few scientific data about clinical efficacy and safety. A great problem of herbal drugs regards the concomitant use of conventional drugs that may lead to an alteration of the pharmacokinetics and/or pharmacodynamics of the drug, with severe and perhaps even life-threatening adverse effects. Thus, herb-drug interactions are the aim of many studies both in vitro and in vivo. In the present study herb-drug interactions between botanicals active on central nervous system and conventional drug has been reviewed. Botanicals included in this review were divided into three major classes: anxiolytics (Passiflora incarnata L., Valeriana officinalis L., Matricaria recutita L., Lavandula angustifolia M., Humulus lupulus L., Melissa officinalis L.), antidepressants (Hypericum perforatum L., Rhodiola rosea L., Panax ginseng C.A. Meyer, Crocus sativus L.) and botanicals against brain decline or anti-dementia drugs (Ginkgo biloba L., Curcuma longa L.). Critical review of the literature on this topic was undertaken in order to assess the clinical relevance of herb-drug interactions. 75 clinical trials or case reports were reviewed and 37 drugs were involved in herb-drug interactions. Among herbal drugs considered, ginkgo and ginseng are implicated in a significant number of reports, but many of these are unsubstantiated. Interactions ginseng-alcohol and lavender-citalopram were considered clinically relevant whereas interaction ginseng-warfarin gave conflicting results but seems to be likely. No clinical trials or reports occur for Passiflora incarnata L., Humulus lupulus L., Melissa officinalis L., Rhodiola rosea L. and Crocus sativus L. Herbal drugs active on central nervous system seem to be, in general, safe when properly used. Concomitant use of ginkgo, ginseng and St. John’s Wort with conventional drugs must be managed with caution.