Abstract Title Implementation of a VA Addiction Hotline: Assessing the Impact of Addiction Hotline Intervention on Buprenorphine and Naloxone Prescribing Rates in the Emergency Department Authors Jennifer Diaz, Nathalie Dieujuste, Francis C. Averill, Cynthia Koh, Hemang Acharya, Zahir Basrai, Comilla Sasson, Manuel Celedon Background The opioid crisis in the United States resulted in over 81,000 deaths in 2022. The VeteransHealth Administration (VHA) has supported overdose education and naloxone distribution(OEND) programs and released clinical practice guidelines advocating for the use of medications for opioid use disorder. Despite increased awareness and allocation of resources, uptake of OEND programs has been variable within VHA, and buprenorphine for the treatment of opioid use disorder (OUD) remains underutilized. To improve naloxone and buprenorphine prescribing, we developed a daily telehealth addiction hotline service for VHA emergency department (ED) providers to access an addiction specialist in real-time from 1:00 p.m. to 9:00p.m. PST. We evaluated naloxone and buprenorphine prescribing before and after implementing an addiction hotline in eight Southwest VHA facilities (SW VHA). Methods We reviewed VHA clinical dashboard quarterly performance data of ED naloxone and buprenorphine prescribing from October 1, 2021 through March 31st, 2024 (ten government fiscal year quarters). The dashboard reports a quarterly percentage of prescribing rates for naloxone (number of ED patients at risk for opioid-related overdose prescribed naloxone at discharge divided by the total number of at-risk ED patients) and buprenorphine (number of ED patients with untreated OUD receiving buprenorphine at discharge divided by the total number of ED patients with untreated OUD). We conducted four paired sample t-tests evaluating the changes in trends for naloxone and buprenorphine prescribing from VHA EDs before implementation of the addiction hotline (October 1st, 2021 through December 31st, 2022) and after implementation (January 1st, 2023 through March 31st, 2024). The national VHA data was utilized as a control since the addiction hotline intervention occurred only in Southwest VHA facilities. Results In the national (control) group, naloxone prescribing increased significantly between the pre- implementation period and the post-implementation period with a mean increase of 9.08 (SD=1.36, p<0.001), Cohen's d=6.66. The SW VHA (intervention) group also showed a significant increase of 13.47 (SD=9.29, p=0.032), Cohen's d=1.45. For buprenorphine, the control group displayed a significant increase of 0.73 (SD=0.19, p=0.001), Cohen's d=3.75. The intervention group showed a mean increase of 1.25 (SD=1.26), significant at only the one-tailed level (p=0.04), Cohen's d=0.99. Conclusion Naloxone and buprenorphine prescribing increased significantly both nationally and in SW VHA.A more pronounced increase was observed in SW VHA, indicating a potential positive impact from the addiction hotline. Further investigation is needed to evaluate the effect of a real-time clinician support service on naloxone and buprenorphine prescribing in the ED.