Low-dose buprenorphine initiation shows limited success among fentanyl users with OUD

Key takeaways:

• Only 34% of attempts were successful in low-dose initiation of buprenorphine.
• No significant differences in retention were found between low-dose initiation protocol types.

Low-dose initiation of buprenorphine in an outpatient setting showed low rates of success among a cohort of adults with opioid use disorder who self-reported daily fentanyl use, according to a study published in JAMA Network Open.

The uptake of buprenorphine has been low among fentanyl users due to the challenges associated with severe precipitated withdrawal, according to the researchers.

“The emerging practice of low-dose initiation of buprenorphine presents an opportunity to improve outcomes in the fentanyl era,” Leslie W. Suen, MD, MAS, assistant professor of medicine in the UCSF division of general internal medicine at San Francisco General Hospital, and colleagues wrote.

“Prior case series have discussed the role of low-dose initiation in outpatient settings,” they added. “However, understanding of low-dose initiation outcomes in outpatient settings remains minimal and needed, especially as the majority of buprenorphine initiations occur in the outpatient setting.”

To evaluate outpatient outcomes associated with two low-dose initiation protocols of buprenorphine, Suen and colleagues conducted a retrospective cohort study of 126 adults aged 18 years or older (median age, 35 years; 71% men; 52% white) with opioid use disorder (OUD) and self-reported daily fentanyl use who attempted low-dose initiation of buprenorphine and picked up their prescription from the Community Behavioral Health Services Pharmacy in San Francisco between May 1, 2021, and Nov. 30, 2022.

The primary outcome of the study was successful buprenorphine initiation, which the researchers defined as self-reported completion of the low-dose initiation protocol at a follow-up visit and pickup of a refill maintenance prescription within 1 month of the initiation date.

Across 175 low-dose initiation attempts, 41% (n = 72) used a 4-day protocol and 59% (n = 103) used a 7-day protocol.

Overall, 34% of low-dose initiation attempts (n = 60) were successful, including 27 with the 4-day protocol and 29 with the 7-day protocol, according to the researchers.

At 28 days, the buprenorphine retention rate reached 21% for the 4-day protocol and 18% for the 7-day protocol.

Logistic regression models revealed that there were no significant differences between low-dose initiation protocols and successful initiation.

Additionally, the researchers reported that second attempts (adjusted OR = 0.3; 95% CI, 0.14-0.66) and third or more attempts (aOR = 0.22; 95% CI, 0.09-0.53) were associated with lower odds of successful initiation compared with first attempts.

They also noted that Kaplan-Meier curves showed no significant difference in retention between the 4-day protocol and 7-day protocol.

“Contrary to our hypothesis, people had lower odds of successful initiation with repeated attempts,” the researchers wrote. “Despite this finding, those who return to the clinic after an unsuccessful first low-dose initiation attempt and desiring a second attempt should be allowed to do so to promote autonomy, with clinicians assisting in troubleshooting. However, those with two or more unsuccessful low-dose initiation attempts may be advised to try alternative strategies.”

Suen and colleagues acknowledged several study limitations, including the potential for bias due to retrospective data collection and participants’ selection of the low-dose initiation protocol, as well as potential limited generalizability of the findings to other settings.

“Future studies should examine interventions to improve low-dose initiation success and increase buprenorphine uptake and retention,” the researchers wrote.