Medication and driving

Section 4 of the Road Traffic Act 1988 does not differentiate between illegal or prescribed drugs, as it’s the effect they have upon your ability to drive which is the concern. This means that anyone found driving whilst unfit, due to any drug, could be prosecuted.

People whose driving ability may be impaired through their illness or prescribed medication should inform their insurance company. Failure to do so is considered to be 'witholding a material fact' and may render the insurance policy void.

Not all insurance companies take this information into account and it won't affect your premium. But if they do ask, you should either check this with the company, or assume you have to tell them. See the Motor insurance section for more information.

Many psychotropic drugs can impair alertness, concentration and driving performance. Effects are particularly marked at the start of treatment and after increasing the dose. It is important to stop driving during this time if adversely affected. The use of alcohol will further increase any impairment.

Common effects of psychotropic drugs

Here is a list of the most common effects of psychotropic drugs and alcohol that may affect driving.

  • Hypnotics and anxiolytics
     Benzodiazepines cause sedation and impaired attention, information processing, memory and co-ordination of movement. They have also been associated with increased risk of road traffic accidents.
  • Antipsychotics
     Antipsychotics may impair ability to drive due to sedation and some side effects impairing co-ordination and response time.
  • Antidepressants
     Tricyclic antidepressants have been associated with an increased risk of road traffic accidents. SSRIs and MAOIs may be safer in the long term but probably not during the acute phase of the illness.
  • Anticonvulsants
     Initial, dose-related side-effects may affect driving ability (blurred vision, sedation).
  • Lithium
     Lithium may impair vision in the dark but how this affects driving safety is unknown.
  • Alcohol
     Alcohol causes sedation and impaired coordination, vision, attention and information processing. Alcohol dependent drivers are twice as likely to be involved in traffic accidents, and offences, than licensed drivers. A third of all fatal road traffic accidents involve alcohol-dependent drivers.
  • Other medicines, either prescribed or over the counter, may also be sedative and/or affect driving ability (e.g. antihisthamines).

For more information about psychotropic medication, see Medication.