This is a multisite EMS study that will first conduct a sequence of pragmatic, prehospital field studies to provide preliminary feasibility, acceptability, and safety data for refinement and enhancement of a subsequent single-arm prospective trial that will provide preliminary effectiveness data, from which to build a larger randomized control trail (RCT) trial.

Evaluating the EMS clinical protocol details and subsequent research procedures will be accomplished by enrolling approximately five EMS-initiated BUP encounters per site. Subsequently, a pragmatic field study will engage approximately thirty successful BUP initiations to assess the feasibility, acceptability, and safety of the EMS clinical protocol and follow up procedures. Investigators will also enroll a cohort of up to thirty patients per site who are eligible for BUP but refuse for informative purposes only, to understand reasons for refusal. Qualitative data on the refusal cohort will be analyzed separately. The outcomes of the pragmatic studies will inform revisions to the EMS clinical protocol.

A single-arm prospective trial of approximately 100 patients per site will subsequently be conducted to collect preliminary data on the effectiveness of EMS-initiated BUP on engagement in MOUD treatment within 10 and 30 days after the EMS-initiated BUP encounter.

Inclusion Criteria:

• 18 years of age or older
• Treated by the EMS-Initiated buprenorphine clinical protocol which includes:

Patients that accept EMS-Initiated BUP protocol. Patients offered the EMS-Initiated BUP protocol but declined.1

• Willing to follow study procedures.
• Able to speak English sufficiently to understand study procedures, and to provide verbal and electronic/written consent.

Exclusion Criteria:

• Patients who lack decision making capacity
• Patients who are in police or protective custody

Individuals in the prehospital setting with OUD 1) presenting with overdose requiring naloxone reversal or 2) in acute opioid abstinence withdrawal offered an EMS clinical protocol across approximately three ED-EMS systems.

In line with the National Institutes of Health Helping to End Addiction Long-term (NIH HEAL) Initiative Public Access and Data Sharing Policy, publications and underlying primary data will be made available to the public.

Data will be made available after 1) The primary outcome paper has been accepted for publication, or 2) the data is locked for more than 18 months, whichever comes first.

De-identified scientific data generated from this study will be made available to the public in the NIDA data repository, per NIDA CTN policy and the Data Management and Sharing Plan for the study.