Key Message

• Evidence is inconsistent and of very low to moderate quality for the clinical effectiveness of cannabis regarding treatment retention and adherence, craving and withdrawal symptoms, or illicit opioid or other substance use. There is lack of consensus in the included publications as to whether use of cannabis in opioid use disorder is beneficial or detrimental.
• No evidence of an impact of cannabis on quality of life, functioning, satisfaction, relapse, hospitalizations, or overdoses in people with opioid use disorder was identified.
• One evidence-based guideline developed by health care and allied health professionals in Canada strongly recommends against the use of cannabinoids for the treatment of opioid use disorder in the primary care setting due to no or inconclusive evidence.

Key Message

Limited evidence of the clinical effectiveness of metered-dose inhalers for medical cannabis is available from patients who were prior users of medical cannabis (primarily by smoking) for treating chronic pain, chemotherapy-induced nausea, or spasticity.

No evidence was found for using metered-dose inhalers for medical cannabis in patients who were naive to medical cannabis.

Inhalation of medical cannabis using a metered-dose inhaler delivers low and precise doses of delta-9-tetrahydrocannabinol that provide a rapid onset of action and dose-dependent effects and is generally well tolerated.

No consistent or prolonged cognitive impairment occurred following inhalation of medical cannabis using a metered-dose inhaler in patients who had previously used medical cannabis for their medical condition.

No evidence was found that directly compared inhalation of medical cannabis using a metered-dose inhaler versus consumption of medical cannabis by an alternate route such as smoking, vapourizing, vaping, dabbing, mucosal administration, or oral ingestion.

No evidence-based guidelines were identified for using metered-dose inhalers for medical cannabis to inform best practices.