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.