Engaging an unstably housed population with low-barrier buprenorphine treatment at a syringe services program: Lessons learned from Seattle, Washington.

: Clinic-imposed barriers can impede access to medication for opioid use disorder (MOUD). We evaluated a low-barrier buprenorphine program that is co-located with a syringe services program (SSP) in Seattle, Washington, USA. : We analyzed medical record data corresponding to patients who enrolled into the buprenorphine program in its first year of operation. We used descriptive statistics and tests of association to longitudinally evaluate retention, cumulative number of days buprenorphine was prescribed, and toxicology results. : Demand for buprenorphine among SSP clients initially surpassed programmatic capacity. Of the 146 enrolled patients, the majority (82%) were unstably housed. Patients were prescribed buprenorphine for a median of 47 days (interquartile range [IQR] = 8-147) in the 180 days following enrollment. Between the first and sixth visits, the percentage of toxicology tests that was positive for buprenorphine significantly increased (33% to 96%,  < .0001) and other opioids significantly decreased (90% to 41%,  .0001) and plateaued thereafter. Toxicology test results for stimulants, benzodiazepines, and barbiturates did not significantly change. : SSP served as an effective point of entry for a low-barrier MOUD program. A large proportion of enrolled patients demonstrated sustained retention and reductions in opioid use, despite housing instability and polysubstance use.