Relevance of published blood concentrations of new psychoactive substance for rational case interpretation

New psychoactive substances (NPS), as substitutes for classic drugs of abuse, are still very popular although the number of newly detected compounds slightly decreased in the last 2 years. Nevertheless, the number of published fatality and poisoning cases showed that they are far from harmless. The most relevant drug classes by number are synthetic cannabinoids and synthetic cathinones/phenethylamines. Synthetic opioids are the most dangerous compounds due to their potency and life‐threatening effects, such as respiratory and central depression. In contrast to pharmaceutical drugs, no clinical studies were mandatory before entering the drug market thus no information is available on their toxicity, pharmacokinetic properties as well as their effective and/or toxic concentration ranges. Published case reports may therefore be very helpful to estimate the risk of a respective NPS but only if some requirements were fulfilled. Main demands on such case reports are analytical confirmation and quantitation of the ingested NPS, screening for other potentially relevant central acting drugs and quantification, if appropriate, as well as documentation of the clinical signs, and other circumstances, such as the time between the observations and blood sampling and existing diseases and/or genetic variations. Based on the given information of as much as possible cases with the same constellation, reliable statements on effective/toxic concentration ranges should be possible. This article is categorized under: Toxicology > New Psychoactive Substances Toxicology > Analytical Toxicology Toxicology > Drug Analysis