Comparing fatal cases involving U-47700.

U-47700 (3,4-dichloro-N-[2-(dimethylamino)cyclohexyl]N-methylbenzamide) is a novel compound with opioid properties, developed by Upjohn in the 1970s and derived from the earlier opioid analgesic AH-7921 (3,4-dichloro-N{[1-(dimethylamino)-cyclohexyl]methyl}benzamide) [1]. U-47700 is a structural isomer of AH-7921 [2]. AH-7921, which possesses the same potency as morphine, was first identified in 2012 in a seizure purchased over the internet and recently entered the recreational and illicit drug market as new psychotropic substance in Japan, the USA, and Europe [3]. U-47700 was never studied in humans and is not registered for medical use in humans. Very little, if any, information on it is available in scientific literature [2, 4]. Since the substance is not scheduled or controlled, it is openly sold on the internet as an opioid ‘legal high’. Anecdotal evidence from user reports on specialized internet drug fora reveals that U-47700 is actively being used as a legal substitute for other strong opioids, such as morphine, heroin, or even fentanyl [3]. U-47700 is only controlled in Finland and Sweden (the latter since 1/26/ 2016). U-47700 is approximately 7.5 times more potent than morphine [3]. Interestingly and surprisingly, there are only two fatal case reports in the literature [2, 3] involving U-47700. Remarkably, both cases involved young adult males, one is a 30-year-old, the other is a 27-year-old; one in Belgium (Case A), the other in UK (Case B). Authors of both papers claimed their case to be the ‘‘first’’ fatality case involving U-47700, which is understandable, as not only both incidents happened roughly at the same time, i.e., January, 2016, but both reports were published roughly at the same time, i.e., May, 2016. A PubMed search using ‘‘U-47700’’ returned only two entries, i.e., the reports by Coopman et al. and Elliott et al. We would like to compare and comment on these two reports. In Case A, published in Forensic Science International, Coopman and colleagues [3] describe a 30-year-old man, found dead in his home after inhaling fumes of a powder burned on aluminum foil. Blood and urine were taken by the medical examiner during the external body examination and submitted to the laboratory for a comprehensive systematic toxicological analysis. A toxic fentanyl level of 10.9 lg/L was measured from a subclavian blood sample. A powder found in the victims’ home was transferred to the laboratory for analysis, in which trace amounts of fentanyl (0.0035 %, m/m) and U-47700 (0.0012 %, m/m) were identified by gas chromatography mass spectrometry. The blood and urine U-47700 concentrations were 13.8 and 71.0 lg/L, respectively. Coopman and colleagues report that based on circumstantial evidence (police investigation, crime scene) and the results of the toxicological analysis, the medical examiner concluded that the cause of death was an acute intoxication and overdose with fentanyl and U-47700, ‘‘immediately after inhaling the fumes of the vaporized powder.’’ It was presumed the death was & Xiulu Ruan [email protected]