UKCan I be prosecuted for driving while on prescription medication?
Yes, you can be prosecuted for driving while impaired by prescription medication if it affects your ability to drive safely — the law treats impairment from legal drugs the same as from illegal ones.
What the Law Says
The Road Traffic Act 1988 makes it a criminal offence to drive or attempt to drive while unfit due to drugs — including prescription medicines — if your driving is impaired.
Section 4 of the Road Traffic Act 1988 creates the offence of driving or being in charge of a motor vehicle while unfit through drugs. It applies regardless of whether the drug is prescribed, over-the-counter, or illegal — what matters is whether it impairs your ability to drive safely.
The law does not excuse impairment just because a doctor prescribed the medication. You are responsible for knowing how a medicine affects you and whether it’s safe for you to drive.
If a police officer suspects you’re unfit, they can require a field impairment test (e.g., balance, coordination, or eye tests) and, if necessary, a blood or urine sample for laboratory analysis.
Statutory TextA person who, when driving a motor vehicle on a road or other public place, is unfit to drive through drugs shall be guilty of an offence.
— Road Traffic Act 1988, s. 4 — Driving or attempting to drive while unfit through drugs
What to Do
Check the patient information leaflet (PIL) for warnings about drowsiness, dizziness, blurred vision, or impaired reaction times.
Ask your doctor or pharmacist whether it’s safe to drive while taking the medication — especially when starting, changing dose, or combining with other drugs.
Do not drive if you feel sleepy, confused, uncoordinated, or otherwise impaired — even if the medicine is prescribed.
Keep records of prescriptions and medical advice in case you need to explain your position to police or in court.
If stopped and asked to take a field impairment test, cooperate fully — refusal without reasonable cause is itself an offence.
Sources
Not legal advice. This article is general information based on publicly available sources, written for educational purposes. Laws change and individual situations vary. Consult a licensed attorney in your jurisdiction before acting on anything you read here. Last reviewed: 2026-06-08.