“Opioid never event” (ONE) is a proposed classification to describe dependence or overdose among opioid-naïve patients prescribed opioids at hospital discharge. Based on a retrospective review of medical records of patients at one academic medical center, researchers estimated that the ONE affected approximately 2 per 1,000 opioid-naïve surgical patients and persistent opioid use 90 to 360 days after surgery was present in 45% of patients with ONEs.