"All it's gonna tell you is if it has fentanyl or not:" Perceptions of fentanyl and drug checking among first responders and people who use drugs.

Introduction: Fentanyl contamination in the unregulated drug supply contributes to high rates of opioid overdose among people who use drugs (PWUD). Drug checking is a harm reduction strategy that provides PWUD with information about the contents of their substances. Although drug checking has broad utility, this study focused specifically on drug checking to test for fentanyl, with a particular emphasis on fentanyl test strips (FTS) and point-of-care testing at community service organizations. This study assessed first responders and PWUDs' perceptions of fentanyl, drug checking, and associated implementation suggestions.

Methods: The risk environment framework and community-engaged methods guided the study. First responders and PWUD were recruited using convenience sampling from first responder agencies and community service locations, respectively, in King County, WA. The study conducted semi-structured interviews with first responders (n = 32; law enforcement officers, paramedics, emergency medical services, firefighters, etc.) and PWUD (n = 13) until data saturation. A group of academically trained and peer-based researchers with lived experiences of substance use analyzed the data using a thematic analysis approach.

Results: First responders and PWUD discussed the fentanyl-saturated drug use landscape and the amplification of PWUDs' overdose risk. Preferences for fentanyl among PWUD varied, ranging from a preference for it, to willingness to use it, to strong aversion. Most first responders expressed concerns about post-overdose FTS distribution, viewing it as ineffective in promoting safer use behaviors and inconsistent with their workflow and provider role. People who use fentanyl perceived drug checking to be of low relevance due to fentanyl's ubiquity, while PWUD who were trying to avoid it cited numerous barriers, including low availability, trust in sellers, limitations of FTS, and lack of information or connections.

Conclusions: The study found low support for drug checking for fentanyl and first responders' distribution of FTS. Drug checking may have the most utility for PWUD who were trying to avoid fentanyl; however, its potential benefits may not be fully realized until structural barriers to access and use are addressed. Caution should be exercised to not promote drug checking as a universal tool and place the onus of addressing fentanyl contamination on PWUD.