ObjectivesWe aimed to clarify the prevalence, indications, analgesic comedications and complications of prescription opioid use in patients presenting to a large emergency department (ED).DesignRetrospective chart review.SettingLarge, interdisciplinary ED of a public hospital.ParticipantsAll patients aged ≥18 years presenting between 1 January 2017, and 31 December 2018, with documentation on medication were included.InterventionsNone.Primary and secondary outcome measuresPrevalence rates for prescription opioid use and its indication. Prevalence of analgesic comedications in prescription opioid users. Hospitalisation rate, 72 hours ED reconsultation rate, 30-day rehospitalisation rate, in-hospital mortality.ResultsA total of 26 224 consultations were included in the analysis; 1906 (7.3%) patients had prescriptions for opioids on admission to the ED. The main indications for opioid prescriptions were musculoskeletal disease in 1145 (60.1%) patients, followed by neoplastic disease in 374 (19.6%) patients. One hundred fifty-four (8.2%) consultations were directly related to opioid intake, and 50.1% of patients on opioids also used other classes of analgesics. Patients on prescription opioids were older (76 vs 62 years, p<0.0001) and female individuals were over-represented (58 vs 48.9%, p<0.0001). Hospitalisation rate (78.3 vs 49%, p<0.0001), 72 hours ED reconsultation rate (0.8 vs 0.3%, p=0.004), 30-day rehospitalisation rate (6.2 vs 1.5%, p<0.0001) and in-hospital mortality (6.3 vs 1.6%, p<0.0001) were significantly higher in patients with opioid therapy than other patients. In 25 cases (1.3%), admission to the ED was due to opioid intoxication.ConclusionsDaily prescription opioid use is common in patients presenting to the ED. The use of prescription opioids is associated with adverse outcomes, whereas intoxication is a minor issue in the studied population.