Opioid agonist treatment (OAT) is the first-line treatment for opioid use disorder (OUD). Simultaneously, opioids are essential medicines in acute pain management. The literature is scarce on acute pain management in individuals with OUD, and guidelines are controversial for patients on OAT. We aimed at analyzing rescue analgesia in opioid-dependent individuals on OAT during hospitalization in the University Hospital Basel, Switzerland.; Patient hospital records were extracted from the database over 6 months (Jan-Jun) in 2015 and 2018. Of the 3,216 extracted patient records, we identified 255 cases on OAT with full datasets. Rescue analgesia was defined according to established principles of acute pain management, e.g., i) the analgesic agent is identical to the OAT medication, and ii) the opioid agent is dosed above 1/6th morphine equivalent dose of the OAT medication.; The patients were on average 51.3 ± 10.5 years old (range: 22-79 years), of which 64% were men. The most frequent OAT agents were methadone and morphine (34.9% and 34.5%). Rescue analgesia was not documented in 14 cases. Guideline-concordant rescue analgesia was observed in 186 cases (72.9%) and consisted mostly of NSAIDs, including paracetamol (80 cases), and identical agents such as the OAT opioid (70 cases). Guideline-divergent rescue analgesia was observed in 69 (27.1%) cases, predominantly due to an underdosed opioid agent (32 cases), another agent other than the OAT (18 cases), or contraindicated agents (10 cases).; Our analysis suggests that rescue analgesia in hospitalized OAT patients was predominantly concordant with guidelines, while divergent prescriptions seemed to follow common principles of pain medicine. Clear guidelines are needed to appropriately treat acute pain in hospitalized OAT patients.