BACKGROUND: Naloxone is a li fe-saving, yet underprescribed, medication that is recommended to be provided to patients at high risk of opioid overdose. OBJECTIVE: We set out to evaluate the changes in prescriber practices due to the use of an electronic health record (EHR) advisory that prompted opioid prescribers to co-prescribe naloxone when prescribing a high-dose opioid. It also provided prescribers with guidance on decreasing opioid doses for safety. DESIGN: This was a retrospective chart abstraction study looking at all opioid prescriptions and all naloxone prescriptions written as emergency department (ED) discharge, inpatient hospital discharge, or outpatient medi-