N-Pyrrolidino protonitazene was found in samples sold as heroin in Dublin and Cork, Ireland, in late 2023. These were associated with numerous overdose events which prompted a rapid multi-agency response, with two government and two academic laboratories working closely together to identify the compound(s) responsible. The process highlighted the strengths and weaknesses of techniques commonly used in forensic drug analysis, and a nonroutine technique, nuclear magnetic resonance (NMR) spectroscopy, was required for confirmation.

Abstract

Synthetic opioids have been associated globally with adverse effects in drug users. The nitazene group of drugs is a relatively new addition to the synthetic opioid class emerging in Europe in 2019. Some nitazenes have been shown to be more potent than fentanyl. Overdose clusters in heroin users in Dublin (57 cases) and Cork (20 cases), Ireland, in November and December 2023, respectively, prompted a rapid response from a number of Irish laboratories to identify the substance(s) of concern. Light brown (tan) powders were obtained from cases associated with overdoses, and the results from these analyses by collaboration of four laboratories are reported here. The samples were found to contain N-pyrrolidino protonitazene (protonitazepyne), caffeine, paracetamol, benzoic acid and mannitol.