Changing characteristics in the 2020s of fatal 'novel' benzodiazepine toxicity cases in Australia.

Abstract

Deaths due to poisoning involving novel benzodiazepines (NBZDs) are increasing. We aimed to determine: 1. The characteristics, toxicology and major autopsy findings of known cases of NBZD-related poisoning in Australia, 2000-2025; and 2. Changes in characteristics of known cases from 2020 onwards compared to earlier known cases. Retrospective study of fatal NBDZ-related poisoning in Australia retrieved from the National Coronial Information System. 258 cases were identified, the first in 2013 (2013-2019: 33, 2020-2025: 225). The mean age was 31.9 years and 217 were male, which did not change. 2020s cases were more likely to have histories of injecting drug use (52.0v 21.2 %, OR 4.0) and mental health issues (55.1v 30.3 %, OR 2.8). Fifteen NBZDs were detected, nine first detected in the 2020s. The most frequent were etizolam (48.9 %) and bromazolam (38.0 %). Cases in the later period were more likely to have multiple NBZDs detected (39.6v 12.1 %, OR 4.7). The most common other drug classes were opioids (74.8 %) and registered hypnosedatives (62.4 %). There were no differences between cases in the later and earlier periods in the presence of depressants (94.7v 93.9 %), or psychostimulants (52.0v 39.4 %). Acute bronchopneumonia was less common in the later period (18.2v 40.0 %, OR 1.5). The 2020s saw a large increase in poisoning deaths related to NBZDs. As testing varied across time and jurisdiction and new NBZDs are constantly appearing the true extent of NBZD-related poisoning deaths is likely to be higher than those identified.