Objective: To describe the impact of an educational intervention for ED prescribers on discharge oxycodone prescribing both for the number of oxycodone prescriptions per 1000 discharged patients, and the number of tablets per prescription. Secondary outcomes included the quality of general practitioner communication. Methods: An interrupted time series assessment was conducted in the ED of a tertiary referral hospital to establish the pre-intervention, periintervention and post-intervention prescribing profile of ED medical practitioners. Prescriber numbers were used to obtain drug data for all oxycodone-containing prescriptions from the Queensland Health Medicines Regulation and Quality Unit database. The intervention included education sessions, a staff information email, posters within the ED, and a patient brochure. It was conducted with relevant nurses, pharmacists and prescribing doctors. Results: In the pre-intervention period, 656/17 371 (38 per 1000) discharged patients were prescribed oxycodone, compared to 180/5938 (30 per 1000) during the intervention, and 602/20 505 (29 per 1000) post-intervention. This equated to a decrease of 8 per 1000 (95% CI 5-12 per 1000) and a 22% (95% CI 13-31%) relative prescribing reduction. The mean total number of tablets of oxycodone per prescription decreased from 16.7 (SD 16.5) preintervention, to 12.7 (SD 6.0) periintervention, to 10.7 (SD 5.2) postintervention. After the intervention, there was an increase in discharge communications to general practitioners by 15.4% (95% CI 9.7-21.1%). Conclusions: An ED prescribertargeted intervention reduced overall prescribing of oxycodone and improved communication at discharge. The prescribing intervention is one strategy that may be used by ED medical staff to improve patient safety and opioid stewardship in Australia.