Clinical characterisation of the novel benzodiazepine bromazolam-data from the ASSIST (A Surveillance Study of Illicit Substance Toxicity) study.

Introduction: Scotland has a drug death crisis. In 2023, 58% of drug-related deaths involved benzodiazepines. Novel benzodiazepines, predominantly bromazolam, are found in the drug "street valium", commonly used in Scotland. This study describes features of analytically confirmed bromazolam use.

Methods: This observational study was conducted at the Queen Elizabeth University Hospital, Glasgow between 17 August 2022 and 16 February 2024. The study used data from a larger surveillance study (A Surveillance Study of Illicit Substance Toxicity, clinicaltrials.gov, NCT05329142). Emergency department attendances with moderate to severe illicit substance toxicity and positive detection of bromazolam were included. Toxicological analysis was performed on anonymised samples in the Laboratory of the Government Chemist Assure laboratory using ultra performance liquid chromatography interfaced with Thermofisher Q-Exactive Orbitrap high resolution accurate mass systems. The study has full ethical approval (West of Scotland Research Ethics Committee 22/WS/0047).

Results: Of 1,188 adult attendances with illicit drug toxicity, 653 qualified for toxicological analysis. Two-hundred ninety-nine (45.8%) of these involved bromazolam with increasing rates seen within this study from 22.7% in quarter 1 to 58.3% in quarter 6. The median age was 42 years (IQR: 34-50 years) and 214 (71.6%) were male. The median number of illicit substances detected in samples with bromazolam was seven (IQR: five to nine). The most common clinical feature was reduced consciousness (238 patients, 79.6%) and 37 patients (12.4%) required critical care admission.

Discussion: Rates of bromazolam detection increased within the population studied, aligning with Scottish drug death figures. Though clinical features presented in this study cannot be fully attributed to bromazolam alone due to high substance co-use, reduced consciousness was frequent.

Conclusion: High rates of substance co-use inhibit our ability to fully understand specific features of bromazolam toxicity, however, this study highlights its prevalence in this population and identifies clinical features in positive detections.