Medicinal Cannabis and Driving

This page is about Victoria’s road safety laws and how they relate to your medicinal cannabis prescription. If you have any questions regarding your specific health and driving circumstances, please consult your health care professional. 

You’re legally required to tell VicRoads if you have or develop, a long-term medical condition, disability, or injury that could affect your fitness to drive. You also need to tell VicRoads if your driving ability might be compromised by the effects of medical treatment or medication. Find out what happens after you notify VicRoads.

Can I drive while taking medicinal cannabis? 

Many medicinal cannabis products contain Delta-9-tetrahydrocannabinol (THC). It is an offence in Victoria for a person to drive with any amount of THC in their system, including any amount of THC from medicinal cannabis. Penalties for drug-driving include a mandatory driver licence suspension and monetary fines.

It is also an offence to drive a motor vehicle whilst impaired by any substance or prescription medication, including medicinal cannabis.

All drivers who are taking medications should be aware of the potential for impairing effects. They should check the product information for their medication and talk with their doctor and pharmacist about possible effects on fitness to drive. Further information for drivers regarding self-assessment of fitness to drive can be found at medicines and road safety.

Patients taking cannabidiol-only medicines can lawfully drive, as long as they are not impaired. Drivers should check whether the medicinal cannabis product they have been prescribed contains THC. Many medicinal cannabis products do not contain THC. This should be stated clearly on products, but drivers should also verify this with the professional who has prescribed the medication, or their pharmacist. 

All patients should ensure that they are purchasing their prescription through legitimate channels to avoid the possibility of inadvertently taking a product that contains THC when it claims to be THC free.

Why is it illegal to drive while taking medicinal cannabis containing THC?

THC is a psychoactive substance that has shown to impair cognitive and motor function, increasing your risk of being involved in a motor vehicle crash. Impairments that will affect your driving include your ability to anticipate hazards and unexpected situations, your decision making and your ability to respond quickly to changes in the traffic environment (e.g. reaction time). These impairing effects are exacerbated when combined with alcohol and certain other prescription medication. Patients should not drive or operate machinery while being treated with medicinal cannabis products containing THC.

Does all medicinal cannabis contain THC?

Medicinal cannabis comes in different cannabinoid formulations and therefore the amount of THC will vary between products. Speak to your health care professional regarding your specific prescription.

How do Victoria Police test for THC? 

Victoria Police conduct random roadside drug testing throughout Victoria. Roadside drug testing requires the driver to provide a small sample of saliva for testing. A saliva sample that is positive for THC at the roadside will be sent to a laboratory for confirmation. A confirmed positive test will result in a drug-driving charge.

It is an offence to not:

  • stop at a random drug testing station
  • provide a saliva or blood sample
  • cooperate with police who are trying to carry out a saliva, blood or urine test, or
  • cooperate to take part in a drug impairment assessment.

Can a valid prescription be used as a defence against a drug-driving charge involving medicinal cannabis? 

A valid prescription for medicinal cannabis cannot be used as a defence against a charge of testing positive for THC on a roadside drug test.

When taking medicinal cannabis containing THC, how long does THC remain in my system? 

The length of time that THC remains in a person’s system is highly variable and depends on a range of pharmacological and metabolic factors, including the amount of THC in the product, how it was prepared and how it is taken (e.g. vaporised and inhaled, sprayed into the mouth or nose, placed under the tongue or swallowed in a capsule).

There has been very limited research to date investigating how long THC from medicinal cannabis remains in a person’s system. It is therefore not currently possible to provide definitive advice. Please note that TGA approved product information states that patients taking Sativex® should not drive.

What happens if I am involved in a motor vehicle crash while taking medicinal cannabis? 

All drivers involved in a crash in Victoria that results in death or injury are required by law to provide a blood sample to Victoria Police for analysis. The presence of THC (including THC from medicinal cannabis) in blood can be used as evidence for prosecution purposes and may also affect vehicle and personal injury insurance claims.

Where can I find more information?

Speak to your health care professional to discuss your specific driving circumstances. 


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