Background <p>Over 50% of patients do not take their medications as prescribed or are non-adherent. Primary care providers are well positioned to address non-adherence. However, current methods for obtaining adherence are unreliable. RxFill integrates prescription medication fill status and dispense dates from community pharmacies into clinic electronic health records (EHRs). The goal of this study was to examine RxFill usability during a simulated case with primary care providers.</p> Methods <p>The study took place at an academic health system that implemented RxFill in June 2022. Participants were asked to review a simulated patient chart and “think aloud.” After, a semi-structured interview elicited attitudes towards RxFill, including usability. Participants also completed the System Usability Scale (SUS), which scores the functionality on a scale of 0-100. Think-aloud commentary and interview transcripts were analyzed via qualitative content analysis.</p> Results <p>Eight providers participated in the study. The average SUS score was 81.25, generally considered “Acceptable.” Qualitative themes included RxFill usefulness, ease of use, and fit into current workload. Participants reported RxFill data was useful to estimate patient adherence, however, running reports for each medication was time intensive. Participants had minimal time to review patient charts prior to appointments, which would limit their ability to use RxFill in practice.</p> Conclusions <p>RxFill data, although useful, was not entirely easy to use and did not fit into participants’ current workload. Institutions implementing RxFill should make dispense dates and fill indicators easy to access and consider workload and integration into other health IT systems. Additionally, RxFill use is limited by community pharmacy adoption and the ability to send fill data.</p> Clinical trial registration <p>Not applicable.</p>