Why are Nitazenes so dangerous and how can we ameliorate their harm?

The UK's National Crime Agency has recently warned that nitazenes pose a significant threat. These Novel Synthetic Opioids, like heroin and fentanyls, activate the mu-opioid receptor and are increasingly found in street heroin as supplies of heroin dwindle. Nitazenes are also emerging in party drugs (e.g., Ecstasy, 2C-B), cocaine, and illicit vapes. Several nitazenes are more potent than heroin and fentanyl, posing a severe risk of escalating overdose and death rates among the UK's 300,000 opioid users and over 1 million Class A drug users. Since June 2023, nitazenes have been linked to around 300 deaths, with this figure likely to rise. Particularly concerning is evidence that naloxone, the standard opioid antidote, is less effective at reversing nitazene overdoses compared to heroin overdoses. Currently there are ~40 known nitazenes and new chemical variants continue to appear. Despite their increasing prevalence, our understanding of nitazene pharmacology, including their interaction with opioid receptors and the mechanisms driving their potent effects, remains limited. Addressing this knowledge gap is critical for developing effective interventions and treatments for nitazene-related toxicity. Our project will comprehensively investigate the pharmacology of nitazene drugs through an innovative, multidisciplinary approach. We have assembled a team of 7 Project lead/Co-leads who are all technical experts and world leaders in the field of opioid research. By combining ligand-receptor molecular modeling, in vitro pharmacology, ex vivo brain slice electrophysiology, and in vivo respiratory studies, we aim to uncover the mechanisms underlying the high potency and dangerous side effects of nitazene analogs. Our goal is to provide detailed insights into the molecular interactions, cellular responses, and physiological impacts of these drugs, laying the foundation for the development of targeted therapies to mitigate their harmful effects. Our focus will be on: Identifying the most potent and dangerous nitazenes, and understanding the chemical basis of this potency to assess future risks from emerging nitazenes. Determining which nitazenes require higher doses of naloxone for overdose reversal and explaining the interaction between nitazenes and antagonists at the receptor level. Identifying properties that could enhance antagonist efficacy, aiding in the development of novel antagonists for better clinical reversal of nitazene overdoses. Access to a collaborator's library of ~100 new nitazenes, some with antagonist properties, will support this effort. Whether individual nitazenes, in addition to centrally depressing respiratory rate, also have the potential to cause respiratory muscle stiffness, further restricting breathing capacity. Evaluating whether heroin use or medically assisted treatments offer any protection against nitazene overdose, crucial for assessing future nitazene risks. Our multidisciplinary approach will be informed by real-world data from our partners at the Bristol Drugs Project, and aims to build a comprehensive model of nitazene action from molecular to systemic effects. Through this, we hope to inform better strategies for prevention, treatment, and harm reduction.