Quick reference guide

Currently, Section 4 of the Road Traffic Act 1988 includes an offence of driving whilst impaired through drugs, regardless of whether or not the drugs are being used legitimately. This means that if a patient’s driving is found to be impaired by medicines, even if he or she is taking them as prescribed or as recommended in the product information, he or she may still be prosecuted.

A new additional offence of driving with certain specified drugs in excess of specified levels will come into force on 02 March 2015 in England and Wales. The legislation also provides for a statutory "medical defence" for patients taking their medicines as prescribed or in accordance with product information.

Roadside drug screening devices will use saliva to identify if a driver has taken one of the drugs listed below, or a drug that is metabolised to one of these. The first group are commonly abused drugs for which low limits have been set, the second group consists mainly of licensed medicines that have a significant liability to be abused and the specified limits have been set higher than those for the first group.