The Opioid PrEscRiptions and Usage After Surgery (OPERAS) study aimed to quantify the current global practice of opioid prescribing and consumption patterns in patients after discharge from common surgical procedures, and to identify factors associated with increased opioid consumption. It found that double the quantity of opioids patients consume in the post-discharge period are prescribed at discharge, exposing them to risk of opioid-related harm. Individualised opioid prescribing at discharge remains important as excess prescriptions are driving increased consumption of opioids by patients. While patient pain levels and pre-discharge opioid consumption influence opioid consumption at discharge, the quantity of opioids prescribed remains a modifiable factor to curtailing excessive prescriptions of unused opioids.