Assessment of a County-Wide, Pan-First Responder Take-Home Naloxone Program in Denver, Colorado

To evaluate the feasibility and geospatial distribution of a county-wide pan-first responder leave-behind naloxone program implemented across emergency medical services (EMS), police, fire, and a community response mobile crisis unit.

We conducted a retrospective analysis of leave-behind naloxone kits distributed in Denver, Colorado, from April 26, 2024, through April 25, 2025. Trained first responders (n ∼2850) recorded each kit distribution via an online form capturing location, agency, recipient category, and transport disposition. Descriptive statistics were used to summarize kit distributions by agency and transport outcomes. A hotspot analysis mapped clusters of distributions and assessed proximity to transit stops and other public facilities.

Over the 12-month period, there were 1020 interactions during which responders distributed 2438 naloxone kits. Paramedics accounted for 1407 kits (57.7%), the mobile crisis unit for 642 (26.3%), police for 336 (13.8%), and fire for 53 (2.2%). In many interactions, the kit recipient declined transport, particularly in the mobile crisis unit and EMS cohorts. Geospatial analysis identified 24 hotspots, of which 23 were within feasible walking distance of bus or light-rail stops. These findings suggest that leave-behind naloxone distributions cluster around transportation hubs in Denver.

A pan-first-responder leave-behind naloxone program is feasible at the county level, with most kits distributed by paramedics and a mobile crisis unit program. Hotspot analysis highlighted transit-adjacent clusters, informing potential sites for prestationed naloxone. Cross-agency collaboration combined with geospatial targeting may rapidly saturate high-risk settings with naloxone.