Diphenidine: a dissociative NPS makes an entrance on the drug scene

Purpose Diphenidine is a potent synthetic dissociative anesthetic drug that has recently emerged in drug markets of Europe, Japan and America. The aim of this review is to summarize the current knowledge about this drug concerning its chemistry, synthesis, prevalence, pharmacology, toxicology and metabolism, as well as its legal status. Analytical methodologies developed for the determination of diphenidine in biological specimens and published diphenidine-related intoxications, fatal or not, are also presented. Methods All the reviewed information was gathered through a detailed search of PubMed and the World Wide Web using proper keywords. Results Diphenidine is not approved for medical or veterinary use, but it is used illicitly around the world for recreational purposes or as a substitute of other controlled dissociative drugs. It is available through the Internet in powder form for oral administration, smoking or vaporization. Since its first appearance in the drug market in 2013, seizures have been reported worldwide and its abuse has already caused intoxications and deaths in Europe and Japan, thus leading to its scheduling in the United Kingdom and Canada during the second semester of 2016. Conclusions Diphenidine is a harmful dissociative drug that recently gained serious concern for public health. International and local authorities should take all the appropriate actions and measures to avoid the expansion of this new threat.