Medical cannabis and driving

Check out our handy guide on driving with medical cannabis

If you have a prescription for medical cannabis and drive, you might worry about what steps you should take to drive safely. We have put together a guide to help answer any questions you might have.

Can I drive whilst taking medical cannabis?

Like many everyday medicines, your driving ability may be reduced (driving impairment) while you are taking your medical cannabis. Your medication may cause drowsiness and can initially reduce your reaction times. This can increase your risk of having an accident, putting yourself and others at risk.

You only need to inform the DVLA of your medical condition, not your prescription. And only if your medical condition affects your driving. The only condition that medical cannabis is commonly prescribed which requires an individual to inform the DVLA is epilepsy. However, it’s recommended that people prescribed medical cannabis inform the DVLA and their car insurance company of their prescription to avoid the risk of losing insurance coverage in case of a collision.

Learn more about speaking with the DVLA about your medical conditions by visiting

It’s always best to avoid driving or tasks that require fine motor skills until you know how your medication affects you. Some of the times your driving risk is likely to increase are listed below:

  • Starting medical cannabis for the first time
  • After a change in dose, most likely after an increase in dose

A statutory defence may apply if a car accident occurs where a specialist doctor has legally prescribed medical cannabis and driving performance was not impaired.

The current legal limit for blood tetrahydrocannabinol (THC) levels is 2micrograms/L. It’s highly likely that if you’ve been prescribed medical cannabis preparations containing THC, you will exceed this limit.

THC can show up in your blood within minutes after taking your medication. THC is also stored in fat cells and is slowly released. This means that THC can still be detectable in your blood stream well beyond 28 days.

No matter your medication, you should never drive whilst impaired. Your dose and prescription can affect you differently from someone else, so you should always speak to your specialist doctor about possible impairment while taking your medication. Cannabidiol (CBD) only products have been shown to have no potential effect on driving reaction speed and risk of collision.

Can I carry my medical cannabis in my car?

It’s possible that the police may stop you whilst you are taking your prescription.

You’ll need to provide proof that you have been legally prescribed your medication, so it’s a good idea to keep your clinic letters and/or prescriptions with you even if you’re not carrying your medication on you.

The law gives the police power to test drivers they think are driving under the influence. This law includes a medical defence that if you’re prescribed medical cannabis and taking your medication as directed by your specialist doctor, providing you’re not impaired, then you’re not breaking the law.

You can learn more about the driving laws and medical defences here.

In a typical roadside screening test, the police would not be able to tell the difference between medical or recreational cannabis in your blood. This means that if you did take a screening or drug test, you would likely produce a positive result. This is why it is important to carry copies of any evidence supporting your medical condition and prescription (such as a copy of your prescription and a clinic letter from your specialist doctor, along with your ID), so you can show the police at the earliest possible time. You don’t have to if you feel uncomfortable, but it may also help to have a document from your specialist doctor detailing your medical condition, such as chronic pain, epilepsy, or multiple sclerosis, so the police are aware in case you need further medical assistance.

The police should allow you to proceed if they’re satisfied that you’re taking your medication as directed, under the supervision of your specialist doctor, and that you’re not impaired while driving.

If you have any questions or concerns, please speak to your prescriber or one of our team at Curaleaf Pharmacy.

Useful sources

For further information and a more detailed report of medical cannabis and driving, please read Medical cannabis and road safety: A research report for the Department for Transport.

Please note that this page is for advice and is correct at the time of writing. You should always consult the latest guidance.