What happens if I take drugs and drive?

If you drive after taking drugs, your ability to drive may be impaired and your reactions could be slower. Amphetamines, cannabis, cocaine and ecstasy are just some examples of illegal drugs known to cause impairment.

Driving under the influence of a drug (including any side effect) is illegal and is controlled by two offences under the Road Traffic Act 1988: driving in excess of a specified limit for certain drugs specified in regulations; and driving while unfit through drink or drugs.

The current UK law defines a drug as "any intoxicant other than alcohol". This includes illegal drugs such as cannabis, as well as prescribed medicines and over-the-counter medicines. This is because a driver who is impaired through any drug is at risk of having an accident. Drug driving is considered to be as serious as drink driving, and the penalties are the same.

How drugs affect driving

Drugs affect your ability to drive in many ways. For example, you may experience:

  • slower reaction times
  • erratic (unpredictable) and aggressive behaviour
  • poor concentration
  • distorted perception (false sense of awareness and understanding of, for example, distances) 
  • poor coordination
  • blurred vision
  • overconfidence that leads to you taking unnecessary risks
  • nausea (feeling sick)
  • hallucinations (seeing, feeling or hearing things that are not real)
  • panic attacks
  • paranoia (being suspicious of people and situations)
  • tremors or shaking
  • dizziness
  • tiredness, which can be severe, and sometimes last until the following day

The effects can vary according to the individual person, drug type, dosage, the length of time the drug stays in your body, or if the drug has been taken with other drugs or alcohol. The effects can last for hours or days.

Police roadside tests

The police can carry out tests at the roadside to check if a driver is above the specified limit for certain specified drugs; these can also help the officer decide if the driver is impaired. Refusing to take the tests is an offence, and the driver can be arrested in the same way they can be for failing to provide a breath test when under suspicion of drink driving. For more information, see Is there a police test for drug driving?

What happens if I'm caught?

If you're found guilty of driving under the influence of drugs, the penalties are the same as for drink driving. You will receive:

  • a minimum one-year driving ban
  • a fine of up to £5,000, up to six months in prison, or both
  • a criminal record

A conviction for drug driving is shown on your driving licence for 11 years. If you drive for work, your employer will see the conviction when you produce your licence.

Any drug-related conviction may cause problems visiting countries such as the US.

Medicines and driving

Medicines that can affect your ability to drive include:

  • prescribed medicines – such as antihistamines or tranquillisers
  • over-the-counter medicines – such as co-codamol

Medicines that can make you feel sleepy will carry a message saying: "Warning. May cause drowsiness. If affected, do not drive or operate machinery".

Always ask your GP or pharmacist if your medication may affect your ability to drive. Also check:

  • the medicine's packaging
  • the patient information leaflet that comes with your medicine

You can find out which health conditions or medical treatments you may need to tell the DVLA about on their website. For more information, see Driving with a disability or health condition

Alternatively, you can call NHS 111 for advice.

If in doubt, don't drive.

Read the answers to common health questions about alcohol, drugs and smoking.

Further information:

Saying no to drugs

Would you say no to drugs? Find out what choices teenagers Taz and Mike made, and how their lives were affected.

Media last reviewed: 18/06/2015

Next review due: 18/06/2017

Page last reviewed: 28/08/2014

Next review due: 27/08/2016