Treatment outcomes after initiating buprenorphine/naloxone or methadone for opioid use disorder among First…

Cohort studyThe International journal on drug policy· Sep 2026

Treatment outcomes after initiating buprenorphine/naloxone or methadone for opioid use disorder among First Nation Peoples in Ontario, Canada.

Nevena Rebić, Sacha Bragg, Daniel McCormack … Tara Gomes

Addiction MedicineCohort study

Buprenorphine/naloxone was associated with lower risk of opioid toxicity than methadone among First Nation Peoples in Ontario

Treatment outcomes after initiating buprenorphine/naloxone or methadone for opioid use disorder among First Nation Peoples in Ontario, Canada.

Nevena Rebić … Tara Gomes

The International journal on drug policy · Sep 2026

Background

The Canadian opioid toxicity crisis has disproportionately harmed First Nation Peoples.

Methods

Our population-based cohort included First Nation Peoples in Ontario, Canada, who initiated buprenorphine/naloxone or methadone between October 1st, 2016 and March 31st, 2021.

Results

Weighted hazard ratio for opioid toxicity in the first year; buprenorphine/naloxone versus methadone (95% CI, 0.45-0.93).

HR 0.65 (95% CI 0.45 to 0.93)

null 1

0.45

0.93

CI excludes the null - significant

More results

We included 3270 and 2186 First Nation individuals initiating buprenorphine/naloxone and methadone, respectively.

Findings were consistent when stratified by residence and sex.

More results

Females initiating buprenorphine/naloxone had a lower risk of opioid toxicity (wHR 0.35; 95% CI, 0.19-0.66), a difference not observed among males (wHR 0.95; 95% CI, 0.60-1.50; interaction term p-value=0.01).

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Conclusion · 1 of 2

The safety and accessibility of buprenorphine/naloxone supports First Nation-led efforts expanding its availability in rural and remote regions of Ontario.

Conclusion · 2 of 2

Higher methadone retention rates underscore the need for equitable access to opioid agonist treatment options for First Nation Peoples, regardless of where they live.

Treatment outcomes after initiating buprenorphine/naloxone or methadone for opioid use disorder among First Nation Peoples in Ontario, Canada.

Treatment outcomes after initiating buprenorphine/naloxone or methadone for opioid use disorder among First Nation Peoples in Ontario, Canada.

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