Identification of the novel synthetic opioid N-pyrrolidino isotonitazene at an Australian drug checking service.

2-Benzylbenzimidazole opioids and related derivatives, also known as ‘nitazenes’, present a growing threat to public health. Emerging in Europe in 2019, the nitazene group of drugs is a recent addition to the novel synthetic opioid class and has been associated internationally with adverse effects in drug users, overdose clusters and significant mortality. The high potency of many nitazene derivatives, which can in many cases exceed that of fentanyl, poses a significant challenge to the public health and early warning systems used to detect and respond to the emergence of new high-risk substances. This report describes close collaboration between an Australian drug checking service and a nearby university laboratory to identify and characterise the novel synthetic opioid N-pyrrolidino isotonitazene in an expected oxycodone sample presented by a member of the public. Though no prior publications are available describing the presence of this nitazene in the drug market, previously reported in vitro evaluation of this compound reveals it to be among the most potent nitazene opioid agonists known. The study highlights the rapid response possible though engaging drug users with drug checking services as a market monitor and early warning system to alert health services and the broader community to the presence of unexpected, high-risk substances. Integration of well-resourced and supported drug checking services provides a powerful approach to tackle the public health threats associated with new synthetic opioids and other drugs of concern.