PROJECT SUMMARY From May 2020 to April 2021, more than 100,000 individuals died of a drug overdose, making it the leading cause of injury death in the United States.[1] The increase in the overdose death rate has primarily been borne by American Indian/Alaska Native (AI/AN) and Black people, with the overdose rate of AI/ANs (29.8/100,000) and Blacks (27.3/100,000) now exceeding that of non-Hispanic Whites (23.6/100,000).[4] In North Carolina (NC) from 2019 to 2020, the overdose death rate increased by more than 75% for AI/ANs and 52% for Blacks, compared to a 19% increase for non-Hispanic Whites.[25] Distributing naloxone, an opioid overdose reversal agent, is an effective method for reducing opioid overdose deaths.[5, 6] The majority of overdose deaths involve opioids, including the synthetic opioid, fentanyl,[26] which has prompted large-scale national efforts to increase naloxone availability.[5] Naloxone can be purchased at community pharmacies and is also distributed for free by community-based entities, such as syringe service programs (SSPs). Unfortunately, recent studies have documented racial and geographic disparities in access to naloxone, which may contribute to growing disparities in opioid overdose deaths.[7-10, 14, 31] To our knowledge, no comprehensive measure of naloxone availability has been reported in the literature. Most studies of naloxone availability assess single sources, such as pharmacies[11-16] or community-based programs,[17, 18] leaving an incomplete picture of total community-level access. Our objective is to develop a novel, comprehensive place-based measure of naloxone availability in order to document disparities in naloxone access. For Aim 1, we will work with an Advisory Board to create a novel, comprehensive place- based measure of naloxone availability. We will combine primary data collected from a secret shopper study of community pharmacies and surveys of NC’s naloxone distribution entities with secondary insurance claims data to comprehensively document sources of naloxone by ZIP code. For Aim 2, we will estimate disparities in naloxone availability for: (1) AI/AN and Black communities; (2) rural populations; and (3) populations at high- risk of an opioid overdose.[20, 21] For Aim 3, we will identify how social and community factors, such as community-level social segregation and drug-related arrests, mediate the relationship between geographic location and racial disparities in naloxone availability. This study will result in the development of visual tools and maps that display racial and geographic disparities in availability so that naloxone-distributing entities can coordinate efforts to ensure equity in naloxone distribution to prevent opioid overdose deaths. We will also disseminate our measurement development framework so it can be readily replicated in other states.