Evaluation of a Pharmacist-Integrated Model of Opioid Use Disorder Treatment to Increase Naloxone Co-Prescribing in Primary Care - PROJECT SUMMARY In the United States overdose deaths remain at near record highs, largely due to the proliferation of fentanyl in the illicit opioid supply. Increasing access to the opioid overdose antidote, naloxone, to people at high risk of experiencing or witnessing an overdose is a public health intervention shown to reduce overdose death. Nearly half of the US states have a provision related to prescribing naloxone to patients at risk, namely patients prescribed medication for opioid use disorder, known as co-prescription. However, research suggests most states are not distributing or co-prescribing enough naloxone to prevent 80% of witnessed overdose deaths. While the most recent federal approval of the first over-the counter (OTC) naloxone formulation will help increase access for people who can afford OTC naloxone, it is unknown how this approval may affect access for people receiving medication treatment for OUD in primary care. Co-prescribing naloxone in primary care has the potential to fill what has been a persistent gap in the overdose crisis response. There is growing literature that pharmacists can help to increase naloxone co-prescription. The NIDA Clinical Trials Network 0116 study (PI: Marsch) is ongoing and aims to evaluate the feasibility, acceptability, and impact of implementing a pharmacist-integrated model of medication treatment for OUD (PrIMO) in four primary care sites in four states. The objective of this F31 application is to investigate whether PrIMO may increase primary care capacity for co-prescribing naloxone within the parent study. The research project aims to: (1) Describe federal, state, and clinic-level policies and current OUD interventions which impact co-prescribing naloxone within four PrIMO primary care sites in four states. (2) Investigate care team knowledge and attitudes regarding naloxone, emerging OTC naloxone guidance, and patient overdose across PrIMO implementation, and (3) Evaluate naloxone co-prescribing to patients receiving medication treatment for OUD by patient demographics, provider type, health insurance, urine drug test results, and (b) test if these associations become stronger or weaker across PrIMO implementation. The training plan outlines four learning objectives: (1) gaining descriptive and historical knowledge of the breadth of naloxone policies across different states in the U.S, (2) proficiency with performing longitudinal qualitative interviews with participants as well as proficiency with qualitative analysis techniques relevant to clinical trial implementation and evaluation. (3) proficiency with multi- level modeling relevant to primary care electronic medical record data and (4) developing as a professional academic scientist. These objectives will be achieved with the support and commitment of the mentor, consultant team, and institution. This proposal supports the applicants long-term research agenda to reduce opioid overdose deaths by facilitating greater access to naloxone and evidence-based models of OUD care.