Like many medicines, medical cannabis can impair your driving ability by causing drowsiness and slowing reaction times, increasing the risk of accidents. The current legal limit for blood tetrahydrocannabinol (THC) levels is 2 micrograms/L. It is highly likely that if you have been prescribed medical cannabis containing THC, you will exceed this limit. Cannabidiol (CBD) only products have been shown to have no potential effect on driving reaction speed and risk of collision.
You only need to inform the DVLA if you have a notifiable medical condition or disability. You do not need to inform them about your prescription.
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.
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.
