Driving after cannabis use leads to a 22% increase in the risk of being involved in a motor
vehicle accident due to short-term negative impacts on reaction time, motor coordination,
and divided attention.
The College of Family Physicians of Canada recommends that patients who receive
authorization to use medical cannabis be counseled not to drive for at least:
• 4 hours after inhalation
• 6 hours after oral ingestion
• 8 hours after inhalation or oral ingestion if the patient experiences euphoria
Regardless of how much time has passed, a patient should never operate a vehicle
or heavy machinery or engage in any hazardous activity if impaired.