The Department for Transport has launched a campaign to remind people taking medicines to check they are safe to drive before driving ahead of a change in the law.

New drug-drive legislation comes into force from 2 March in England and Wales, reducing the legal limits for various drugs, some of which are prescription drugs.

The law is designed to catch people who get behind the wheel after taking drugs, and not those who take legitimate medicines that don’t impair their ability to drive.

Government road safety charity Think advises drivers taking high doses of prescribed medication to carry evidence with them when driving to minimise any inconvenience.

The DfT said that so long as a driver is following the advice of a healthcare professional and their driving isn’t impaired by their medication, they can continue to drive as usual and aren’t at risk of arrest.
The DfT said it has set the limit at a very low level for eight drugs commonly associated with illegal use. Eight prescription drugs are included within the new law and these are: 

  • cloanzepam
  • diazepam
  • flunitrazepam
  • lorazepam
  • oxazepam
  • temazepam
  • methadone
  • morphine

However, the limits that have been set for these drugs exceed normal prescribed doses, meaning that the vast majority of people can drive as they normally would, so long as: 

  • they are taking their medicine in accordance with the advice of a healthcare professional and/or as printed in the accompanying leaflet
  • their driving is not impaired

The DfT said there will be a medical defence if a driver has been taking the medication as directed, and is found to be over the limit but not impaired.

Robert Goodwill, Road safety minister, said: “If you are taking your medicine as directed and your driving is not impaired, then you are not breaking the law and there is no need to worry.

“We advise anyone who is unsure about the effects of their medication or how the new legislation may affect them, to seek the advice of their doctor or pharmacist.”

The DfT has created a video to explain the changes:

Table of drugs and limits

‘Illegal’ drugs (‘accidental exposure’ – zero tolerance approach) Threshold limit in blood
benzoylecgonine 50µg/L
cocaine 10µg/L
delta-9-tetrahydrocannibinol (cannabis) 2µg/L
ketamine 20µg/L
lysergic acid diethylamide 1µg/L
methylamphetamine 10µg/L
MDMA 10µg/L
6-monoacetylmorphine (heroin) 5µg/L
‘Medicinal’ drugs (risk based approach) Threshold limit in blood
amphetamine (regulations were recently laid with the proposed limit and expected to come into force after 2 March 2015) 250µg/L
clonazepam 50µg/L
diazepam 550µg/L
flunitrazepam 300µg/L
lorazepam 100µg/L
methadone 500µg/L
morphine 80µg/L
oxazepam 300µg/L
temazepam 1,000µg/L