Dr Caroline Copeland leads a research group at King’s College London in the field of drug-related mortality and harm reduction. As Director of the National Programme on Substance Use Mortality (NPSUM), she has led extensive analyses of coroner-reported drug deaths to identify emerging trends and inform public health responses. Dr Copeland’s research integrates toxicology, epidemiology, and public policy, with a goal of understanding the pharmacological and societal drivers of drug-related mortality. She has published over 45 peer-reviewed papers since 2020, advancing knowledge on the role of prescription medications, novel psychoactive substances, and drug–drug interactions in overdose deaths. Alongside her research, she serves on the UK’s Advisory Council on the Misuse of Drugs and is an expert consultant on novel psychoactive substances for the European Union Drug Agency, providing crucial evidence to shape national and international strategies on drug harm prevention.

Abstract

Nitazene deaths are likely being underestimated due to their degradation in post-mortem blood samples

Nitazenes are potent synthetic opioids that have entered the UK drug market. Following several case reports from post-mortem toxicologists of results indicating nitazene instability in post-mortem blood samples, we aimed to test this using an in vivo rat model, and estimate the number of deaths due to nitazene use that have been missed as a result. Blood and urine samples were taken from rats overdosed with a nitazene on post-mortem day 1 and day 7 to test pre-sampling nitazene stability. These samples were tested immediately and then again 4 weeks later to test post-sampling nitazene stability. Deaths reported to the National Programme on Substance Use Mortality (NPSUM) from the Birmingham area were evaluated for excess deaths. Significant degradation was observed, both pre- and post-sampling with an average of only 16% of the nitazene detected in the immediate day 1 blood samples detectable in the day 7 samples stored in a fridge for 4 weeks. Exponential smoothing models predict that deaths due to nitazene use may be being underestimated by 30%. Nitazenes are unstable in post-mortem blood samples, likely leading to an underestimation in the number of deaths which they have caused. Toxicologists and coroners need to be aware of this in deaths suspected to be due to nitazene use. Commissioners of public health strategies targeting nitazene use need to ensure that they are adequately designed and funded to address the full scale of the problem.