The Emergence of Deschloro-N-ethyl-ketamine, a Ketamine Analog, in Drug Seizures and Drug Driving Cases in Hong Kong

Abstract

The study reports the detection of a newly emerged drug, deschloro-N-ethyl-ketamine (2-oxo-PCE), an analog of ketamine, through forensic drug and toxicological examinations of exhibits from drug seizure cases and blood samples taken from drivers of driving under the influence of drug (DUID) cases, respectively, in Hong Kong. The submission of 2-oxo-PCE in both types of cases was firstly encountered in October 2017. A total of 31 drug seizure cases (52 items) and 4 DUID cases were found positive with 2-oxo-PCE till October 2018. Drug seizures with 2-oxo-PCE found were all in physical form (mostly in powdery or crystalline solid), resembling those samples commonly found with ketamine but having much lower purity. Although the majority of the relevant items was found with 2-oxo-PCE as the only psychoactive substance (36 items, ~69%) or as a mixture with ketamine (10 items, ~19%), other psychoactive substances including methamphetamine, methylenedioxymethamphetamine and pentylone have also been encountered (6 items, 12%). For the four DUID cases, 2-oxo-PCE and its metabolite, deschloronorketamine, were detected in all blood samples. The 2-oxo-PCE concentrations in the four blood samples were in the range of 0.08-0.31 μg/mL, being higher than the concentrations of deschloronorketamine (in the range of 0.04-0.09 μg/mL) for each sample. The 2-oxo-PCE levels found were generally lower than the ketamine levels found in reported DUID cases. With items found with 2-oxo-PCE, which were physically indistinguishable from ketamine but having lower drug purity in seizures, the lower 2-oxo-PCE blood levels with more severe impairment signs observed for the drivers in DUID cases, it is not unreasonable to speculate that users might have taken it as ketamine without knowing of its real identity and hence was adversely affected by the more potent 2-oxo-PCE.