PROJECT SUMMARY Prescription Drug Monitoring Programs (PDMPs) are state administered electronic registries of controlled-substance prescription dispensing data and are used by clinicians to inform prescribing decisions for medications of abuse. Now operating in every state and the District of Columbia, PDMPs are a central strategy in the nation’s response to the opioid overdose epidemic. A growing literature suggests that state PDMPs reduce high-risk opioid prescribing and opioid-related overdoses, particularly in states that mandate use in certain clinical situation. However, PDMP use varies among clinicians because access often entails interrupting the clinical workflow or patient care encounter. To promote increased PDMP use, multiple states are investing in technology that facilitates PDMP integration in other health information technology (HIT) platforms such as the electronic health record (EHR). In an effort to accelerate integration, the Oregon Health Authority is subsidizing PDMP EHR integration for healthcare systems across Oregon. Oregon Health & Science University (OHSU), one the largest healthcare systems in the state, will be one of the first healthcare systems to undergo PDMP integration within its EHR application (Epic™). OHSU is currently integrating PDMP access across twelve ambulatory primary care medicine clinics over a six-month period (four clinics starting every two months). The objective of this proposal is to evaluate the effect of PDMP integration on provider use and prescribing behavior. We accomplish this objective with two Specific Aims: (1) Determine the effect of PDMP EHR integration on provider PDMP use and, (2) Evaluate the effects of PDMP EHR integration on controlled substance prescribing. We will use an observational stepped-wedge design with data derived from OHSU EHR and the state’s PDMP program. We exploit the staggered implementation across OHSU clinics to estimate the effects of PDMP EHR integration on provider use of the PDMP (Aim 1) and prescribing behavior (Aim 2). Data generated from this project will inform PDMP integration efforts across the country and support a larger research proposal to study the effects that initiative on opioid prescribing and opioid-related overdose outcomes.