Objectives: Policy reforms are being considered to increase methadone treatment (MT) access for opioid use disorder in the United States. Proponents of more structured MT reference risks of diversion, including non-prescribed use or redistribution of methadone, and overdose as arguments for limiting access to specialty settings. However, the scientific evidence behind these claims has not been thoroughly reviewed. Methods: We conducted a narrative review of studies on methadone diversion, diverted methadone-involved overdoses, and how these compare in countries with specialty-care-only policies (methadone dispensed only through regulated treatment programs) versus general physician-prescribing policies (physicians prescribe methadone in office-based settings). A narrative approach was chosen, given substantial heterogeneity in study designs, diversion definitions, outcome measures, and data sources. We synthesize and discuss findings from international papers published before October 2025. Results: We identified 29 articles studying methadone diversion or diverted methadone-involved overdoses in 7 countries. Lifetime methadone diversion occurrence varied between 6% and 68%, and using diverted methadone occurrence varied between 22% and 88%. Diverting methadone was most often done to help sick friends/partners. Common reasons for using diverted methadone were preventing withdrawal and avoiding opioid use. Three studies found no association between self-reported diverted methadone use and increased individual-level risk of overdose. Conclusions: The link between specialty-care-only policies and lower diversion and overdose risk is not supported by the reviewed literature. Policymakers should weigh diversion risks against benefits of lives saved through expanded MT access. Further research is needed to better understand the circumstances related to diverted methadone and inform policy-making that appropriately mitigates risks.
Miller et al. (Mon,) studied this question.