Harm Reduction

Lower-Risk Cannabis Use Guidelines

A summary of ten recommendations for lower-risk cannabis use:

1. Abstinence is the most effective way to avoid cannabis use-related health risks
2. Cannabis use should not be started early in life (i.e. definitively avoid use before the age of 16)
3. Choose low-potency tetrahydrocannabinol (THC) or balanced THC-to-cannabidiol (CBD)-ratio cannabis products
4. Do not use synthetic cannabinoids
5. Avoid combusted cannabis inhalation; give preference to non-smoking use methods
6. Avoid deep or other risky inhalation practices
7. Avoid high-frequency (e.g., daily or near-daily) cannabis use
8. Do not drive while impaired by cannabis
9. Populations at higher risk for cannabis use-related health problems should avoid use altogether
10. Avoid combining previously mentioned risk behaviors (e.g., early initiation and high-frequency use).

Full paper is available here:

Fischer B, Russell C, Sabioni P, van den Brink W, Le Foll B, Hall W, et al. Lower-Risk Cannabis Use Guidelines: A Comprehensive Update of Evidence and Recommendations. Public Health Policy. 2017;107(8):e1-e12.

Edibles and Other Newly Legal Forms of Recreational Cannabis

As of October 17, 2019, cannabis extracts, topical cannabis products, and cannabis edibles are legal in Canada. They will be available for sale in licenced dispensaries and online through the Ontario Cannabis Store in December 2019.

• Cannabis extracts are concentrated cannabis products that can be smoked, vaped, or ingested. They contain higher levels of cannabinoids (like THC and CBD) than the cannabis plant contains naturally. Some extracts can be very high in THC; others can mainly contain CBD. Waxes, dabs, and shatters are all examples of cannabis extracts.
• Cannabis topicals are products like oils, creams, and lotions that contain cannabinoids and are intended for use on the skin, hair, or nails. Cannabis topicals are most commonly used for therapeutic or cosmetic purposes rather than to achieve a “high.”
• Cannabis edibles are food or drink items that contain cannabinoids and are intended for ingestion.

For more information about the newly legal forms of Cannabis in Canada, see the Primer on New Cannabis Products from the Canadian Centre for Substance Use and Addiction (CCSUA).

Special Considerations for Edible Cannabis Products

THC, the primary psychoactive component in cannabis, is metabolized differently when it is ingested vs. inhaled. It takes longer to feel the effects of edibles, and the effects typically last longer.

Because of the delayed effects, inexperienced users can be inclined to dose-stack edible cannabis products, which poses a risk for unintentional over-intoxication. Users should give special consideration with respect to driving after consuming edibles (because of the delayed and prolonged effect), and to storing edibles safely to avoid accidental ingestion by children and others.

For more information on edible cannabis and its risks, see the following resources:

• CCSUA’s Inhaling vs. Ingesting infographic
• CCSUA’s 7 Things You Need to Know About Edible Cannabis Resource
• OMA FAQ: Marijuana Decriminalization: The Colorado Emergency Department Experience

Risks

Special Risk Populations

Cannabis may not be suitable for all patients. Several publications from Health Canada, the CFPC, and others have identified a set of special risk populations in the context of both medical and recreational cannabis use:

• Women who are pregnant, breastfeeding, or planning to become pregnant
• Children and youth under the age of 25
• Individuals with current, past, or family history of psychosis
• Individuals with current, past, or family history of substance use disorder

NOTE: Risks to Mental Health

Growing evidence also shows that cannabis use increases the risk of psychosis and psychotic disorders for the general population (not just for those with a history of, or predisposition to psychosis or psychotic disorders).

For a detailed overview of the risks of cannabis use in the populations listed above, and links to position statements from the relevant medical societies, visit our Cannabis and Special Risk Populations page

Cannabis and Driving

Information to help you understand the new laws around cannabis-impaired driving, discuss the risks with patients, and understand your responsibilities.

Cannabis-Related Health care Visits

Marijuana Decriminalization: The Colorado Emergency Department Experience

Toxicologist and Emergency Medicine physician Dr. Kennon Heard draws from the experience of emergency departments in Colorado to comment on the factors that have contributed to the rise of cannabis-related visits to the ER.

He addresses the pharmacology of cannabis and offers practical advice to help Ontario’s Emergency Medicine physicians better prepare for and manage the following cannabis-related presentations:

• Accidental pediatric ingestion
• Cyclic vomiting
• Cannabis intoxication
• Burns
• Synthetic cannabinoid overdoses

Video Lecture

PDF Reference Document

Key Tools

Organization	Title	Description
Canadian Public Health Association	Cannabasics - Information Package	Fact sheets for health and social service providers that give an overview of cannabis plants and products, methods of consumption, and information to better understand harm reduction.
Centre for Effective Practice	Non-Medical Cannabis Resource	Printable resource designed to help providers discuss non-medical cannabis use with their patients in a safe and non-judgmental environment.
Centre for Addiction and Mental Health (CAMH)	Canada’s Lower-Risk Cannabis Use Guidelines	Handout for healthcare professionals summarizing the ten recommendations from the Lower Risk Cannabis Use Guidelines.
Ontario Medical Association	Talking to Patients About Recreational Cannabis	Overview of health risks associated with recreational cannabis use and considerations to guide a conversation with patients about recreational cannabis.
Ontario Medical Association	What You Should Know About Recreational Cannabis - Infographic	Infographic that reviews the basics of cannabis and the risks and harms associated with cannabis use.
Canadian Centre on Substance Use and Addiction	Edible Cannabis, Cannabis Extracts and Cannabis Topicals: A Primer on the New Cannabis Products	Overview of edible cannabis products, cannabis extracts, and topical cannabis products including their uses and effects.
Canadian Centre on Substance Use and Addiction	Cannabis: Inhaling vs. Ingesting	Infographic that outlines the key differences between inhaling and ingesting cannabis and offers tips for lower-risk cannabis use.
Canadian Centre on Substance Use and Addiction	7 Things You Need to Know About Edible Cannabis	Tip sheet that offers seven strategies to reduce harms associated with edible cannabis products.