Interpretative problems due to the presence of chloromethcathinone isomers in the biological material from postmortem cases.

While many new psychoactive substances often disappear from the drug market rather quickly, some, such as synthetic cathinones (SCs), still remain due to their popularity among users. The current knowledge of SC concentrations in blood samples is based mainly on the published case reports of intoxications or fatalities caused by SC intake. The aim of the present study was to present and interpret the obtained toxicological analysis results of these cases, in which it was possible to determine or detect the presence of one of the isomers of chloromethcathinone (CMC) along with its intake biomarker-dihydro-CMC. These cases include 27 deaths reported at the Department of Forensic Medicine in Kraków in 2016-2022. CMC constitutes a major toxicological opinion challenge, in terms of toxicological evaluation of poisonings. As presented in this paper, a significant problem is its stability in the biological material and practices in the reporting of the obtained data. It is therefore important to monitor potential intake biomarkers that may show greater stability in the biological material than the parent drug. In the case of CMC isomers, the good biomarker of intake is the dihydro-CMC metabolite, which was detected in the blood sample in every case presented, even with the absence of the parent substance. Interpretation of the results obtained for CMC in terms of assessing their toxicity and possible cause of death is difficult. However, it should be taken into account that in cases of new psychoactive substance poisoning, an in-depth risk assessment is mandatory and the opinion of the unpredictability of the effects is taken as a principle.