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Clearing the haze: How the legalization of recreational cannabis may affect your medical practice

4 minutes

Published: October 2018 /
Revised: January 2020

The information in this article was correct at the time of publishing

Now that recreational cannabis is legal in Canada, physicians can expect to receive more questions from patients about cannabis for both recreational and medical purposes. This article describes how the legalization of recreational cannabis may impact your medical practice.

Impact on cannabis for medical purposes

Although the federal Cannabis Act1 legalizes and regulates cannabis for personal use, it does not substantively change the legal regime around cannabis for medical purposes, now under the Cannabis Regulations.2

The government purposely kept the legislation governing cannabis for personal use separate from the regime for cannabis for medical purposes. The reasons include ensuring individuals who need cannabis for medical purposes are not limited by the restrictions that apply to recreational use under the Cannabis Act.

For example, some patients may ask their insurer to reimburse them for the cost of cannabis for medical purposes, which presumably will not be possible for recreational cannabis. As well, while there is no age restriction on access to cannabis for medical purposes, the Cannabis Act restricts access to recreational cannabis to persons 18 years of age and older.3 The limits for possession are also different under the two regimes.

The new legislation for recreational cannabis does not change the role you as a physician and nurse practitioners play with respect to cannabis for medical purposes. It is expected patients will continue to ask you for the medical documents needed to access cannabis for medical purposes. When determining whether it is appropriate to complete a medical document for a patient, you should follow the guidelines and policies of your medical regulatory authority (College) that are specific to cannabis for medical purposes. To date, all Colleges except Northwest Territories and Nunavut have issued such guidance.

The Canadian Medical Association website also has guidance for physicians.4

Impact on other aspects of medical practice

Until many of the details concerning the legal use of recreational cannabis are fleshed out in legislation and by-laws at the provincial and municipal levels, it’s difficult to predict its full impact. The parts of your medical practice that may see changes include police requests for blood samples, some clinical practices, and the duty to report patients unfit to operate a motor vehicle.

Police requests for blood samples

You may see an increase in police requests for blood samples from patients suspected of driving while impaired by cannabis, especially if you are an emergency physician. The government has amended the Criminal Code, making it an offence to have a blood drug concentration (BDC) equal to or in excess of the prescribed level for tetrahydrocannabinol (THC) within two hours after driving a motor vehicle. These amendments will also make it somewhat easier for police to demand a blood sample from a suspect, which could result in more requests to physicians.

You may also find that the police have a greater sense of urgency in requesting blood samples from suspected cannabis-impaired drivers than suspected alcohol-impaired drivers. BDC levels, particularly for smoked cannabis, can decline more rapidly after consumption than alcohol so time can take on greater importance for the police.

Despite these amendments and any perceived sense of urgency, you are still not allowed to take blood samples from competent patients without their consent. It is not an offence to refuse to take a sample from an individual in these circumstances.

If you determine a patient is incapable, but the police have obtained a search warrant requiring the taking of blood from this patient, you must comply. The police can only obtain and execute such a warrant if a qualified medical practitioner forms the opinion that the individual is unable to consent to the taking of a blood sample, and taking the sample would not endanger the person’s life or health.

For additional information about search warrants and police investigations, please see the CMPA article, "Physician interactions with police."5

Clinical issues

Cannabis may interact with other medications being taken by a patient. It may also potentially affect a patient’s existing medical condition.

The legalization of recreational cannabis may prompt you to consider more routinely asking patients about use of the substance. This will allow you to better assess the health risks and potential interactions with other medications.6 You should consider discussing with patients the known risks of cannabis consumption on their health. This discussion should be documented in the patient’s medical record.

Fitness to drive

You should also consider whether a patient’s cannabis consumption might render them unfit to operate a motor vehicle safely. Health Canada states, "...it is well known that exposure to [cannabis] impairs psychomotor performance and patients must be warned not to drive or operate complex machinery after smoking or eating cannabis or consuming psychoactive cannabinoid medications (e.g. dronabinol, nabilone, nabiximols)."7

For more information about the duty to report unfit drivers, please see the CMPA’s publication "Hit the brakes: Do you need to report your patient’s fitness to drive?"8 and the Canadian Medical Association’s Driver’s Guide: Determining Medical Fitness to Operate Motor Vehicles (9th ed.),9 which contains a section on cannabis consumption. You may also wish to consult with your provincial or territorial motor vehicle licensing authority about any guidance on the use of cannabis and driving.

Contact the CMPA

You are encouraged to contact the CMPA with any questions concerning medical-legal issues resulting from the legalization of recreational use of cannabis.


  1. Cannabis Act, S.C. 2018, c. 16
  2. Cannabis Regulations, SOR/2018-144, ss 264-353
  3. Most provinces and territories have set 19 years as the minimum age to be consistent with provincial age restrictions for alcohol. In Québec, the legal age to access cannabis is 21. In Alberta, it is 18.
  4. See the CMA’s information on cannabis at www.cma.ca/cannabis
  5. Canadian Medical Protective Association [Internet]. Physician interactions with police. Ottawa (CA):CMPA;2018 Oct [cited 2018 Sept 13]. Available from: https://www.cmpa-acpm.ca/en/advice-publications/browse-articles/2011/physician-interactions-with-police
  6. College of Physicians and Surgeons of Ontario [Internet]. Legalization may see more patients discuss marijuana use. Dialogue, Issue 2, 2018 at 40. Accessed September 10, 2018 from: https://www.cpso.on.ca/cpso/media/documents/publications/dialogue/dialogue_vol14iss2.pdf.
  7. Health Canada, "Information for Health Care Professionals: Cannabis (marihuana, marijuana) and the cannabinoids". Accessed September 10, 2018 from: https://www.canada.ca/en/health-canada/services/drugs-medication/cannabis/information-medical-practitioners/information-health-care-professionals-cannabis-cannabinoids.html#chp771
  8. Canadian Medical Protective Association [Internet]. Fitness to drive: When do physicians have a duty to report? Ottawa (CA);CMPA:2016 Oct [cited 2018 Sept 13]. Available from: https://www.cmpa-acpm.ca/en/advice-publications/browse-articles/2011/physician-interactions-with-police
  9. Canadian Medical Association. Drivers’ Guide: Determining medical fitness to operate motor vehicles. 9th ed. Ottawa (CA):CMA

DISCLAIMER: The information contained in this learning material is for general educational purposes only and is not intended to provide specific professional medical or legal advice, nor to constitute a "standard of care" for Canadian healthcare professionals. The use of CMPA learning resources is subject to the foregoing as well as the CMPA's Terms of Use.