Treatment complements this guideline. The guideline outlines evidence-based standards and regulatory expectations (i.e., what should be done), and the guide provides further details and clinical anecdotes to help readers operationalize the guidelines (i.e., how to do it).# Introduction

# Introduction

# Opioid use disorder and treatment
Opioid use disorder (OUD) is a chronic, relapsing condition that has significant personal, public health and economic consequences. Many of the fatal and non-fatal overdoses in Canada's epidemic over recent years have occurred in people with OUD. OUD may involve prescription medications (including medications that have been diverted from the medical system), or illicitly manufactured opioids, such as heroin or highly potent street fentanyl and fentanyl analogues.
People can achieve sustained long-term remission from OUD with effective treatment and follow-up. The first-line treatment for moderate to severe OUD is opioid agonist therapy (OAT), ideally combined with behavioural and social supports to optimize the determinants of health and address other psychosocial factors that influence substance use and quality of life. OAT can stabilize the cycle of intoxication and withdrawal, reduce opioid cravings and block the intoxicating effects of other shortacting opioids, including fentanyl. People who are maintained on OAT typically experience significantly improved health and social functioning and a considerable reduction in the risk of overdose and all-cause mortality. Some people do not meet criteria for OUD, yet inject or use illicit drugs that can lead to poisonings, overdose and death. This guideline is not applicable to the management of people in these situations, and recommendations for programs and services to address their needs are beyond the scope of this guideline.

# Introduction

# Background
Each provincial medical regulatory authority (MRA) has its own set of guidelines and standards for OAT. The aim of this unified guideline is to standardize expectations for Canadian prescribers, but not to replace any adopted guidelines; rather, this guideline was developed to complement existing initiatives and to support prescribers with best practices and evidence. It serves as a "guideline of guidelines" by synthesizing key recommendations for treating and managing OUD from existing standards, guidelines, expert opinions and best practices across Canada. The role of the MRAs in regulating the management of OUD varies across the country. Some MRAs write clinical guidelines, provide education and have quality assurance programs that ensure safe OAT prescribing, while in other jurisdictions some of these roles are performed by independent organizations. However, what the MRAs have in common is holding registrants accountable to standards of practice. Prescribers should contact their MRA for specific guidance on this guideline and to clarify regulatory expectations for managing OUD.

# Introduction

# Audience
The primary audience for this document is physicians who prescribe treatment for OUD. However, this guideline may be used by other health care professionals who are authorized to prescribe OAT.

# Scope and process
Establishing new evidence was beyond the scope of this project. Rather, the aim was for representatives from each of the participating MRAs and independent reviewers to reach consensus regarding recommendations from existing guidelines (see the "Key opioid use disorder treatment guidelines" section). Targeted searches of peer-reviewed and grey literature were conducted in the cases of guideline discrepancies or topics with varying degrees of evidence. This document is the outcome of that process: it is a product of synthesized guidelines blended with expert opinions and evidence-based literature.
The guideline was developed using an iterative process that involved three groups: a subject matter expert group, an MRA advisory committee and an external reviewer panel. Each MRA nominated two subject matter experts and one MRA representative. The subject matter experts reviewed existing guidelines and literature and helped to develop the recommendations in this document. The MRA representatives reviewed the recommendations to ensure that they conform to regulatory standards. An external panel of clinical experts who do not have clear ties to an MRA, as well as people with lived experience, then reviewed the recommendations. The subject matter expert group considered their feedback in finalizing the recommendations.

# Introduction