Medical Cannabis 101

Cannabis Impairment & Driving

By July 19, 2022 November 1st, 2022 No Comments
Reading Time: 3 minutes

What is cannabis?

Cannabis is a drug that comes from the cannabis sativa plant and is used for both medical and recreational purposes. The cannabis plant contains chemical substances known as cannabinoids which can affect cell receptors in our brains and the bodies. The most well-known cannabinoid is THC, which is the component responsible for the “high” or intoxicating effect of cannabis. The other most well-known cannabinoid is CBD which does not cause any intoxicating effects. It is often used for therapeutic purposes. Naturally occurring cannabinoid receptors in our bodies are involved in the regulation of many bodily functions, including brain and nervous system activity; heart rate and blood pressure; digestion; inflammation; immune system activity; perception of pain, reproduction; sleep cycle; regulation of stress and emotional state.


What Are Signs of Cannabis Impairment?

Cannabis intoxication is more so associated with high THC levels in recreational use and can have both physical and behavioural signs. Someone under the influence of cannabis may portray signs including:

Physical signs: 

-eyes are red, watery or glassy

-dry mouth or shallow breathing

-rapid heart rate


Behavioural signs: 

-delayed reaction time


-inability to focus

-poor coordination

-impaired judgement


Can I Drive After Using Medical Cannabis?

Studies have shown that cannabis can have a negative impact on driving, such as reduced concentration and attention span; slower reaction time, and an altered perception of time and distance. Cannabis also affects a driver’s ability to react to unexpected events. With this said, certain medical cannabis products that are CBD-only should not produce any feelings of intoxication and can be safely taken throughout the day, following your doctors advice. However, you should never drive if you feel impaired or experience side effects even if you have taken only CBD. Similar to any other medications, it is up to the driver to be fully aware, awake, sober, and coherent before making the decision to get behind the wheel. If for any reason you don’t feel completely awake and sober, it is the law for you to wait before driving.


Driving & Cannabis Laws in Canada

Bill C-46, passed in June 2018, established new federal laws and penalties around driving under the influence of cannabis and other drugs.

Three new offences have been created in the Criminal Code of Canada: 

-Driving with 2 nanograms (ng) but less than 5ng of THC per millilitre (ml) of blood results in a $1,000 fine as a summary conviction criminal offence.

-Driving 5ng or more of THC per ml of blood results in a summary or indictable offence and the punishment range from a $1,000 fine to a maximum of 10 years in jail for repeat offenders.

-Driving with a combination of 50 milligrams (mg) of alcohol (or more) plus 2.5 ng (or more) of THC per 1 ml of blood can also be punishable by a  $1,000 fine to a maximum of 10 years in jail for repeat offenders.


Medical cannabis users are not immune to the zero-tolerance drug requirement. They may still face penalties and criminal charges if their ability to drive has been impaired.


Tests for cannabis use in drivers

If the police have a reasonable suspicion that a driver has drugs in his or her body, the police can demand the driver complete a standardized field of sobriety test (SST) or provide an oral fluid sample. As part of Bill C-46 legislation, new oral fluid testing devices are authorized for use by the police. If the driver fails the administered test, the police can then demand a drug recognition evaluation (DRE) by a specially trained officer or demand a blood sample for testing. The oral screening devices are set to a 25 ng threshold, which is significantly higher than the legal driving limits. In order to fail this test, a driver must have above 25 ng per ml of RHC in his oral fluid. The readings at this lever are indicative of very recent use or a high level of impairment.


How Can I Make Sure I’m Safe While Driving?

In conclusion, you should not drive if you have consumed THC products or if you feel impaired in any sort. Be sure to recognize the symptoms of cannabis impairment and educate yourself on the subject. By discussing and working with your medical cannabis healthcare provider, you can follow your treatment plan and be knowledgeable when it comes to your medication. If you want to know more, you can contact us with any questions you have at



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We have reopened two of our clinics in the Toronto area for in-person appointments! If you live in the GTA, we look forward to seeing you in person. Click here to view the two clinics.