Diphenhydramine-involved Fatal and Nonfatal Drug Overdoses in Tennessee, 2019–2022.

Diphenhydramine (DPH), known as the brand name Benadryl, is an over-the-counter medication associated with accidental ingestion leading to nonfatal overdoses. Additionally, DPH has been used in tandem with illicit substances leading to fatal drug overdoses. In response to DPH being seized with illicit drugs as an adulterant, as well as its growing intentional misuse, we sought to explore its recent involvement in fatal and nonfatal drug overdoses in the state of Tennessee. We conducted a statewide cross-sectional study to determine the characteristics of DPH-involved fatal and nonfatal overdoses in Tennessee during 2019–2022 using data from the State Unintentional Drug Overdose Reporting System, the Electronic Surveillance System for the Early Notification of Community-based Epidemics, and the National Forensic Laboratory Information System Public Data Query System. Frequencies were generated to compare demographic characteristics, circumstances, and toxicology between fatal and nonfatal DPH-involved overdoses. We identified 143 suspected nonfatal DPH and 409 fatal DPH-involved overdoses in Tennessee from 2019 to 2022. Nonfatal overdoses remained consistent while fatal overdoses peaked in 2021. Most nonfatal overdoses were under 18 (63.4%), while most fatal overdoses were between 18 and 64 years of age (95.7%). For fatal overdoses, fentanyl was the most prevalent substance on toxicology followed by prescription opioids. Nonfatal overdoses remained consistent while fatal overdoses peaked in 2021 in Tennessee. Use of DPH among other illicit substances lends to evidence suggesting its use as an adulterant. Monitoring of DPH-involved fatal and nonfatal overdoses is critical to inform harm reduction initiatives. [ABSTRACT FROM AUTHOR]