An Update on Deaths in the United Kingdom from ‘Poppers’ (Alkyl Nitrites), with a Particular Focus on ‘Swallowing’ Fatalities

<b>Background/Objectives:</b> Alkyl nitrites are a class of inhalant, commonly known as 'poppers'. Although having medical uses, some other effects include a 'rush', 'high', 'euphoria', or feeling of excitement. This has led to their recreational use, in different scenarios, since the mid-1960s. Adverse effects include tachycardia, migraine headaches, fainting and dizziness, and ventricular fibrillation. Death can occur from the inhalation or ingestion of nitrites. As part of its updated advice to the United Kingdom (UK) Government, the Advisory Council on the Misuse of Drugs considered popper-related mortality, seeking an accurate estimate of deaths. <b>Methods:</b> Data from a range of sources, including specialist mortality databases, were collated and analysed in terms of the key characteristics of decedents and fatal incidents, including the use mode. The chemical names of the nitrites were used in searches. <b>Results:</b> At least forty-two deaths occurred during 1987-2018; two were female. The mean age at death was 44 (range of 20-75) years. Most were White. Most fatalities occurred in England. The specific nitrites mentioned (N = thirty-two) were isobutyl (fourteen); amyl (seven); isopropyl (six); alkyl (three); and butyl (two). The mode of use was only known in 23/42 cases. The product was definitely swallowed in five cases, and very likely in a further one. Four additional cases were identified from the literature and media searches. <b>Conclusions:</b> The lack of a current systematic identification of relevant deaths and shortcomings in historical specialist mortality databases have severely limited what could be established with certainty about these cases. The same criticisms also apply to inhalant mortality data more generally. Nevertheless, the information presented here allows for some conclusions to be drawn and inform UK policy development.