Harm Reduction Engagement and Ongoing Opioid Use Among Adults Receiving Methadone or Buprenorphine in Philadelphia

Background Opioid Use Disorder (OUD), a chronic condition with significant health and social consequences, has been intensified by synthetic opioids such as fentanyl. While medications for OUD (MOUD), such as buprenorphine and methadone, reduce mortality and improve treatment retention, MOUD recipients may continue to engage in high-risk substance use. Harm reduction services (HRSs), including syringe exchange sites, supervised injection facilities, or sites that distribute fentanyl test strips or naloxone, may help mitigate the risks of continued use. This study explores engagement with harm reduction services and opioid use practices among adults receiving MOUD in Philadelphia, including differences in these outcomes between methadone and buprenorphine recipients. Methods We conducted a cross-sectional survey of 116 adults receiving buprenorphine or methadone for moderate-to-severe OUD at three Philadelphia treatment sites between November 2023 and October 2024. The participants completed a RedCAP-based questionnaire assessing recent opioid use, access to and attitudes towards HRS, and substance use practices. Statistical analyses were performed via chi-square and Kruskal‒Wallis tests. Results Overall, 37% of participants reported recent illicit opioid use, primarily via injection with various sterile injection practices. Sixty-one percent of all participants had accessed harm reduction services at least once, yet regular use was uncommon, with only 29% reporting access in the past week. Access to harm reduction services was significantly associated with fentanyl test strip use (p = 0.002) but not with consistent sterile injection practices (p = 0.20). Compared with methadone recipients, buprenorphine recipients were more likely to access harm reduction services, feel welcomed at these sites, recommend them to others, and perceive a positive community impact (all p < 0.05). No differences in recent opioid use were observed between treatment groups or across racial groups. Conclusions Despite active MOUD treatment, many patients reported high-risk opioid use. Positive attitudes toward and engagement with harm reduction services were more common among buprenorphine recipients, suggesting that differences in MOUD setting and structure may influence engagement with harm reduction. These findings support the integration of harm reduction strategies into MOUD programs, particularly among methadone recipients, to reduce risk and improve outcomes among individuals with OUD.