Detection of bromazolam alongside other misused substances

Epidemiological and toxicological data available on patients exposed to bromazolam are limited. We report a case series of 32 patients presenting with bromazolam-positive urines.

Between 1 October and 31 December 2024, 6,083 samples from 5,289 patients presenting to inpatient and outpatient services at four hospitals, were submitted for clinical urine drug screening. Samples were selected for bromazolam confirmation testing if they screened positive for benzodiazepines, fentanyl, cocaine, amfetamines or phencyclidine. A qualitative confirmation method was developed using liquid chromatography tandem mass spectrometry with multiple reaction monitoring.

A total of 2,838 positive urine drug screens underwent confirmation testing. Thirty-five samples from 32 patients were positive for bromazolam. Fentanyl was co-positive in 33 samples (94%). Other prominent combinations included cocaine (n = 27; 77%) and xylazine (n = 24; 69%).

The bromazolam and fentanyl co-positivity suggests that bromazolam may be increasingly found in illicit fentanyl supplies, heightening the risk for respiratory depression and a lack of full response to naloxone. This pattern may also reflect a co-use pattern among opioid users.

The study findings highlight the importance of early warning and toxico-surveillance programs powered with advanced analytical confirmation capabilities for timely detection of emerging new psychoactive substances.