Femoral blood concentrations of the designer benzodiazepine etizolam in post-mortem cases

Etizolam is a thienodiazepine that although licensed for clinical usage in Japan, India and South Korea is commonly abused and detected in post-mortem cases around the world. To date, there are limited data in the literature to allow for the interpretation of blood concentrations of etizolam in post-mortem cases. A liquid chromatography with tandem mass spectrometry method was used to quantitate etizolam concentrations in 28 post-mortem cases where etizolam was detected. The median concentration of etizolam in femoral blood was 8.5 ng/mL (range 1.0-172.0 ng/mL; n = 24); in antemortem plasma, the etizolam concentration range was 4-44 ng/mL (n = 4). The mean age of the individuals abusing etizolam was 38.5 ± 8.4 years (median 39 years), with the majority being male (86%). In all of the cases, multiple drugs were detected, with the most common being pregabalin (61%) followed by morphine/heroin (54%), diazepam (54%) and benzoylecgonine (21%), illustrating the increasing problem of poly-substance use in drug abusers. The cause of death in the cases in which etizolam was detected was multi-drug toxicity in 87.5% of the cases, with 12.5% unrelated to drug use (hangings and blunt-force trauma). These data will further help forensic practitioners with the interpretation of post-mortem etizolam concentrations.