A Phase 2/3 interventional study of Buprenorphine/naloxone in Opioid-use Disorder, sponsored by University of British Columbia. Recruiting at 6 sites in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-24.
Sponsored by University of British Columbia · Phase 2/3, Interventional, and Treatment
This is a multi-centre, open-label RCT at four Emergency Departments (EDs) in British Columbia and Alberta. The purpose of the current study is to compare the effectiveness of buprenorphine/naloxone microdosing and standard dosing take-home induction regimens at enabling patients to successfully complete the induction regimen, and at retaining patients on opioid agonist therapy.
We will randomize our enrolled patients to receive take-home microdosing or standard dosing packages of buprenorphine/naloxone. For the microdosing arm, patients immediately start taking low doses that increase to effective levels without requiring them to go into withdrawal.
We hypothesize that ED patients provided buprenorphine/naloxone microdosing packages will be more likely to successfully complete the induction period compare to patients provided standard dosing packages. We furthermore hypothesize that those provided microdosing will be more likely to be retained in opioid agonist therapy, and will experience lower overdose, mortality, and healthcare utilization subsequent to their ED visit.
This multi-centered, open-label RCT will be carried out at four emergency departments (EDs) across Canada, two in British Columbia (Vancouver General Hospital and St. Paul's Hospital) and two in Alberta (Royal Alexandra Hospital and Northeast Health Centre). The investigators will randomize the selected patients to receive take-home microdosing or standard dosing packages. These will include a five-day regimen in a bubble package, along with over-the-counter adjunctive medication. The details of the different regimens are outlined in the "Study Arms" section of this page, and the adjunctive medication regimen is highlighted below.
The primary objective of the current study is to compare the effectiveness of ED-initiated buprenorphine/naloxone take-home standard dosing and microdosing interventions for patients with opioid use disorder identified at the four study ED's, with regard to a) successful completion of the induction period (primary outcome) and b) retention on opioid agonist therapy at 30, 90, and 365 days following ED visit, or decreasing overdose, mortality and healthcare utilization (secondary outcomes).
The primary outcome measure will be whether the patient filled a prescription for buprenorphine/naloxone within two weeks of their ED visit (binary variable). If this occurs, the investigators presume that the patient successfully completed the induction regimen provided, followed up with a healthcare provider able to prescribe buprenorphine/naloxone, and was subsequently prescribed ongoing buprenorphine/naloxone therapy. The investigators chose a two-week period, recognizing that patients receiving take-home packages from the ED may not start taking the induction regimen immediately after the ED visit, but instead may decide to delay the start of their regimen to a time that is more convenient to them. The investigators hypothesize that most patients would decide to start within two weeks of their ED visit. This hypothesis is supported by peer advisors on the study team.
Secondary outcomes will include retention on OAT, which will be assessed using provincial pharmacy records (PharmaNet and PIN) up to 30, 90 and 365 days.
The investigators will also examine fatal or non-fatal overdose, mortality, ED visits, physician visits, admissions, and days admitted within 30, 90 and 365 days (timeframes plausibly attributable to ED interventions). The investigators expect that successful OAT initiation would lead to decreased healthcare use, consistent with our previous work indicating high admissions among persons with recent OUD diagnoses and OAT discontinuation. The investigators will also assess patients' self-reported experiences with study regimens, withdrawal, precipitated withdrawal, and comfort via participant surveys.
The study will offer co-interventions to both the intervention and control groups that will be outlined in study-related pre-printed clinical ordersets. This will include symptomatic treatment of nausea/vomiting (dimenhydrinate: 50 mg PO q6h prn - 6 doses), and pain or myalgias (acetaminophen: 975 mg po q6h prn - 6 doses) (ibuprofen: 400 mg po q6h prn - 6 doses), to use in the first two days of inductions, when the investigators expect withdrawal symptoms to be most challenging, especially for standard dosing. Those receiving microdosing may experience breakthrough withdrawal if they do not take an adequate dose of overlapping opioid. Of note, enrolled patients will also be offered counselling with ED social workers to aid with social or other patient needs (e.g., housing, transportation).
This RCT builds on interventions, recruitment, and follow-up procedures successfully tested in a feasibility study. The study team has expertise in emergency and addictions medicine, peer engagement, community overdose prevention, biostatistics, health economics, and RCT implementation, including the high-profile SALOME trial comparing heroin and hydromorphone treatments in our target population. Knowledge users from provincial health ministry and regions will ensure scale-up. The study team are engaging people with lived experience throughout study design, implementation, and interpretation to ensure relevance.
The investigators will ascertain our primary and secondary outcome measures relating to completion of induction and retention on OAT, on records of prescriptions filled in provincial pharmacy databases: PharmaNet in BC, and the Pharmaceutical Information Network in Alberta. The investigators specifically selected partner sites in BC and Alberta to allow our team to access these provincial administrative databases for outcome ascertainment, which will minimize losses to follow-up and strengthen the reliability of our results. The investigators will assess secondary outcomes of overdose and mortality by linking our study cohort to the BC Centre for Disease Control Overdose Cohort (for patients enrolled in BC), and to provincial Vital Statistics data (Alberta and BC). The investigators will assess secondary outcomes related to healthcare utilization by linking our study cohort to provincial databases on emergency department visits (National Ambulatory Care Reporting System) and hospitalizations (Discharge Abstract Data) in Alberta and BC. We will access all administrative databases through Population Data BC (PopData BC) and Alberta Health Services.
This trial will inform urgent development of effective ED buprenorphine/naloxone programs to improve OAT access for people at high risk of overdose. The investigators will leverage our networks of policy makers, public health leaders, and health providers to enable rapid dissemination of findings in guidelines and policies across Canada.
1,472 studies on the registry are indexed under Opioid-Related Disorders; 290 are open to participants now.
This study's planned enrollment of 658 is above the median of 63 across 1,166 interventional studies indexed under Opioid-Related Disorders.
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Of its 6 completed or terminated interventional studies of FDA-regulated products, 1 (17%) have results posted.
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We will include ED patients ≥18 years of age with opioid use disorder who are being discharged from the ED. We will define opioid use disorder as non-medical opioid use in the previous 30 days and a positive score for opioid dependency based on the validated Rapid Opioid Dependence Screen (RODS).
All patients will also be assessed by the treating physician or degree of clinical opioid withdrawal, based on the clinical opiate withdrawal scale (COWS) score. Patients will be eligible for the take-home study interventions if they have a COWS score \<=12, as a score greater than 12 would mean the patient is a candidate for standard buprenorphine induction in the ED at that moment in time, and would therefore not be eligible for outpatient study interventions.
Exclusion Criteria:
These factors include:
Participants with Opioid use disorder will receive a Buprenorphine/naloxone microdosing package from the ED. This will consist of a five-day take-home packages with gradually increasing doses of 2mg/0.5mg buprenorphine/naloxone tablet employing a four times daily dosing schedule over five days. Day 1: Buprenorphine 0.5 mg-naloxone 0.125 mg SL\* QID\*\* (One quarter tablet), Day 2: Buprenorphine 1 mg-naloxone 0.25 mg SL QID (One half tablet), Day 3: Buprenorphine 2 mg-naloxone 0.5 mg SL QID (1 tablet), Day 4: Buprenorphine 3 mg-naloxone 0.75 mg SL QID (1.5 tablets) Day 5: Buprenorphine 16 mg-naloxone 4 mg SL once daily (8 tablets). \*SL: Sublingual \*\* QID: four times daily
Drug: Buprenorphine/naloxone
The control intervention will be provision of a buprenorphine/naloxone standard dosing package from the ED. This will consist of a five day package with a commonly accepted standard dosing regimen aiming to achieve a therapeutic buprenorphine/naloxone dose within 24 hours of initiation. Standard dosing packages are currently available in EDs in BC and Alberta as standard of care. Day 1: Buprenorphine 2 mg-naloxone 0.5 mg SL q1h prn to a maximum of 6 tablets in the first 24 hours (1 tablet), Day 2: Buprenorphine 12 mg-naloxone 3 mg SL once daily (6 tablets), Day 3: Buprenorphine 16 mg-naloxone 3 mg SL once daily (8 tablets), Day 4:Buprenorphine 16 mg-naloxone 3 mg SL once daily (8 tablets). Day 5:Buprenorphine 16 mg-naloxone 3 mg SL once daily (8 tablets).
Drug: Buprenorphine/naloxone
Drug pages: Buprenorphine · Naloxone
Buprenorphine/naloxone is a first line, evidence-based opioid agonist therapy that improves mortality for people with opioid use disorder, and that has been demonstrated to be effective at retaining people in addictions care and decreasing illicit opioid use when initiated from EDs.
Also known as: Suboxone
Number of patients who have filled a prescription for buprenorphine/naloxone within two weeks of their ED visit.
Number of patients who have filled a prescription for buprenorphine/naloxone within two weeks of their ED visit.
Time frame: 14 days
Number of patients retained in Opioid agonist therapy (OAT) following the ED visit
Number of patients retained in Opioid agonist therapy (OAT) following the ED visit
Time frame: 30, 90, and 365 days
Number of fatal or non-fatal overdose events, mortality, ED visits, physician visits, admissions, and days admitted to hospital for patients following ED visit.
Number of fatal or non-fatal overdose events, mortality, ED visits, physician visits, admissions, and days admitted to hospital for patients following ED visit.
Time frame: 30, 90, and 365 days.
Plan to share: No — There is no plan to make individual participant data available to other researchers
Started Jul 2021 (actual). Primary completion is estimated for Dec 2027, 77 months after the start.
Of 18 phase 2/3 interventional studies under Opioid-Related Disorders, half reached primary completion within 52 months of starting (the median), counting those still running; a quarter within 35 and three quarters within 85. This study's planned 77 months is above that.
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Studies of the drugs tested here: Buprenorphine · Naloxone
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