Abstract
BACKGROUND: Fentanyl's penetration into the unregulated drug supply has complicated the treatment of opioid use disorder (OUD), particularly by increasing the risk of buprenorphine-precipitated opioid withdrawal (BPOW). Buprenorphine, a partial opioid agonist, remains a first-line treatment for OUD, but traditional induction methods can be intolerable for people using fentanyl. Low-dose induction (LDI), a strategy characterized by gradual buprenorphine titration without prior withdrawal, has emerged as a promising alternative to mitigate BPOW. However, the feasibility and acceptability of LDI in low-barrier, real-world settings such as syringe services programs (SSPs) remain underexplored. METHODS: We conducted a mixed-methods prospective cohort study from June 2023-2024 at an SSP in Miami, Florida, offering a 4-day LDI protocol to patients with OUD who were interested in starting buprenorphine. Follow-up, conducted on a walk-in basis within four weeks, included urine drug screens (UDS), symptom surveys and semi-structured qualitative interviews. The primary outcome was successful buprenorphine initiation, defined by a positive UDS for buprenorphine at follow-up. RESULTS: Of the 30 participants enrolled in the 4-day LDI protocol, most (n = 29) had prior buprenorphine experience and nearly 90% (n = 26) reported past BPOW. Only 16 (53%) returned for follow-up. Nine (56%) of those followed up tested positive for buprenorphine, 11 (68.8%) reported that LDI worked for them, and 12 (75%) said they would use the method again. Qualitative interviews revealed six key themes: (1) LDI mitigates withdrawal symptoms; (2) instructions were helpful but could be improved; (3) fear of BPOW motivated LDI use; (4) LDI enabled autonomy in recovery; (5) unstable living environments hindered adherence; and (6) LDI allowed participants to maintain social roles. CONCLUSIONS: While only 30% of the cohort had objective evidence of buprenorphine induction, most reported successful attempts and found LDI acceptable and empowering. High loss to follow-up and environmental instability limited our conclusions in this outpatient harm reduction setting. Further research is needed to refine LDI protocols and address the structural determinants affecting treatment success among people who use fentanyl.