Over-the-counter antihistamines in drug-related deaths: Health Services Research and Pharmacy Practice Conference

Introduction: Antihistamines are not one of the medicine groups reported on in the Office for National Statistics drug-related death data. (1) However, there is concern that first-generation antihistamines are misused for their sedative properties. This is amplified by a recent social media challenge, which resulted in deaths due to diphenhydramine overdose. (2) The extent of the involvement of antihistamines in deaths is largely unknown. Aim: We aimed to evaluate deaths related to antihistamines in England (2000–2019) by individual drug, medicine classification (POM, P, GSL), whether the drug was considered attributable to the death (known as implication rate), or incidental; and examine temporal trends. Methods: Deaths are reported voluntarily by coroners to the National Programme on Substance Abuse Deaths (NPSAD) in cases where psychoactive drugs were detected at post-mortem and/or when the decedent was known to abuse drugs. NPSAD holds data on decedent demographics (gender, age, employment status, living arrangements), details pertaining to the death (cause(s) of death, manner of death, conclusion of inquest, toxicology reports) and past social and medical histories, including drugs prescribed. From this dataset, we extracted all cases where an antihistamine was detected at post-mortem between 2000 and 2019. We report descriptive statistics to describe the reporting of antihistamines in deaths. Results: We identified 1666 antihistamine detections from 1537 individuals. The significant majority of these were sedative antihistamines which are classed as pharmacy medicines (P) (85.2%, p