Driving and Medical Cannabis
If you are prescribed medical cannabis, it is essential to understand your legal responsibilities when driving. The law in the UK is clear: it is illegal to drive while impaired by any drug, including prescribed medication.
The Law
Under the Drug Driving (Specified Limits) (England and Wales) Regulations 2014, there are specified legal limits for THC in the blood while driving. The limit for THC is 2 micrograms per litre of blood — a very low threshold that may be exceeded by medical cannabis patients.
The Medical Defence
There is a statutory medical defence available to patients who are prescribed cannabis-based medicines. To use this defence, you must be able to demonstrate that:
- The cannabis was prescribed by a specialist doctor
- You were taking it in accordance with your prescription
- Your driving was not impaired
Practical Advice for Medical Cannabis Patients
- Always carry your prescription documentation when driving
- Do not drive if you feel impaired by your medication
- Be aware that THC can remain in your system for extended periods
- Discuss driving with your specialist doctor
- Consider the timing of your doses relative to when you need to drive
Insurance
Inform your motor insurance provider that you are prescribed medical cannabis. Failure to disclose prescribed medications may invalidate your insurance policy.