The first five years of implementing Missouri's medication first approach to opioid use disorder treatment: Plateaus, regressions, and underbellies of progress

Since Missouri's initial implementation of STR/SOR-funded MedFirst, select overall treatment outcomes have improved. Within MedFirst programs, however, outcomes worsened over time, and racial disparities were evident. Though fentanyl's dominance of the drug supply alongside the COVID-19 pandemic contributed to these results, fidelity drift, particularly due to financial implications of MedFirst, likely also negatively impacted sustainability.