Driving and Medicinal Cannabis

What are the rules around using prescribed medicinal cannabis and driving?

It’s illegal in England, Scotland and Wales to drive with legal drugs in your body if it impairs your driving.

Like alcohol in the system, it is difficult to give an absolute figure of what constitutes safe levels in practical terms and so patients should exercise caution when intending to drive if they are taking medication in the lead up to driving.

Like many types of medication, driving while taking prescription cannabis can potentially impair your ability. Effects that may impact driving safely include drowsiness and sedation, impaired judgement, slower reaction time, poorer control of motor skills, lack of concentration, confusion and/or blurred vision.

Many patients prescribed medicinal cannabis would likely test above the legal limit of blood THC levels if drug tested, this is 2µg/L of blood, so patients should not do so if they feel that it impairs their driving.

As such, you must not drive if your cannabis medication causes any of these symptoms. We recommend that you carry a copy of your prescription with you at all times. If necessary, this will prove that your medication has been prescribed and obtained legitimately however this will not be taken as a defence, but at least proves the medication was prescribed legally.

If you’re convicted of drug driving you may get:

• a minimum 1 year driving ban
• an unlimited fine
• up to 6 months in prison
• a criminal record

Your driving licence will also show you’ve been convicted for drug driving. This will last for 11 years.

The maximum penalty for causing death by careless driving under the influence of drugs is life imprisonment.

UK law requires drivers to tell the Driver and Vehicle Licensing Agency (DVLA) about any medical condition that could potentially affect their driving. For certain conditions that may pose an inherent threat to safe driving e.g., epilepsy, the DVLA must be informed.

Prescribers should give patients advice on driving while using medical cannabis. This advice covers the main point that the patient should not drive if they feel impaired, and sometimes includes more specific guidance to support safe consumption. Consideration should also be given to interaction of medical cannabis with other medications especially those likely to impair driving.

So in summary there is no safe limit that can be recommended in general, everyone is different and so whilst at the very least patients shouldn’t drive whilst impaired we would recommend seeking alternative transport options when taking medical cannabis, unless you have sufficient time to ensure that it is out of your system.