What the Guidance Really Says About Medicines and Driving
It is an offence to drive impaired by prescribed medicines, and several common ones impair more than people expect.
Key takeaways
- Offence: driving while impaired by any drug, prescribed or not
- Specified limits: apply to certain drugs including some benzodiazepines and opioids
- Most useful single change: Ask the pharmacist whether a new medicine affects driving.
- Commonest mistake: Driving while drowsy, whatever the cause.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
What it is
The legal and practical rules on driving while taking medicines. It sits within Medicines Safety. What follows are the published numbers, not the ones that get passed around.
The numbers, in one place
| Measure | Figure |
|---|---|
| Offence | driving while impaired by any drug, prescribed or not |
| Specified limits | apply to certain drugs including some benzodiazepines and opioids |
| Statutory defence | available if taking them as prescribed and not impaired |
| Highest risk period | the first days after starting or a dose change |
What helps
These are the changes with the clearest evidence behind them. Start wherever it is easiest to start.
- Ask the pharmacist whether a new medicine affects driving
- Avoid driving in the first days of a new sedating medicine
- Keep evidence of your prescription with you
What to avoid
A few of these are widely believed. That is precisely why they are here.
- Driving while drowsy, whatever the cause
- Alcohol alongside sedating medicines
- Assuming a prescription is a defence if you are actually impaired
Where to go next
- Medicines and Driving: What to Do, in Order
- Popular Beliefs About Medicines and Driving, and What Is Actually Published
- Medicines and Driving — the reference entry
- Storing Medicines: What Published Guidance Supports
- Drug Interactions: Sorting the Evidence From the Noise
When to speak to a doctor
Do not drive if you feel drowsy, dizzy or slowed. Inform the DVLA of any condition affecting driving, including conditions causing excessive sleepiness or severe hypoglycaemia. Seek urgent advice for confusion or fainting on a new medicine.
Where this comes from
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.
Spotted something wrong? Report an error on this page. We correct on the page and say what changed.
