We all know the risks of driving whilst intoxicated and would never dream of getting behind the wheel after drinking alcohol.

However, there are other substances that can have the same effect but those who take them continue to drive, risking harm to both themselves and others.

Prescription medication can be particularly potent, but many drivers overlook the perils and continue to drive while under the influence. We look into the dangers and the legal position if you are caught.


The law

It is illegal to drive with illegal drugs like cocaine or cannabis in your system, even if they are not affecting your driving ability. Similarly, it is illegal to drive while on legal drugs if they affect your driving ability. It is also an offense if you have over the specified limits of certain drugs in your blood and you haven’t been prescribed them.

If you are prescribed any of the following, you should talk to your doctor about whether you are allowed to drive:

You can drive after taking these drugs if:

These laws do not cover Northern Ireland or Scotland.


Penalties for drug driving

If you’re convicted of drug driving you’ll get:

This will last for 11 years.

A conviction for drug driving also means:


How will I know if I am affected?

Everyone is affected by drugs in different ways.

Not everyone suffers the same effects when given medication so it’s important to stay aware of your body when you take ever over-the-counter drugs. There's simply no way of telling in advance how you will respond to a drug.

That’s why it's so important to take care when you are given a new drug. You won't have any idea how it could affect you – and it may affect you differently each time – until you start taking it, so it's best to plan to stay away from the car.

Make sure to read the prescription’s instructions before you take your prescription. Not just for the common side effects so you know what to look out for but also whether it says “do not drive or operate heavy machinery”.  


What are some of the signs to watch out for?

Just like alcohol, prescribed medication has the potential to make an individual feel intoxicated or 'spaced out' and unable to respond to situations as quickly as they need to. This is just one of a range of symptoms which can be triggered by the use of medication, whether prescribed or bought over the counter.

Drowsiness, dizziness, difficulties in concentration as well as effects on hearing and vision are some of the most commonly experienced side effects which mean you shouldn't drive.

Painkillers, antihistamines and sedatives (including some types of anti-depressants) are among the most common types of drugs which can cause significant side effects.

In addition, if you have to take two different types of drug together you may find you suffer symptoms that aren't present if you take either of the medications singly. This is because different drugs can interact with other medications you are taking, creating an unexpected outcome. If you are combining drugs for the first time, you should exercise extreme care.


Where can I find out more information about the effects of medication?

When your doctor prescribes you the medication, they should explain the possible side effects. If none are mentioned you could ask them before you leave.

Doctors have a special book which highlights which drugs are most likely to cause certain side effects, but as mentioned above, this is only a general guide and can't be taken as guaranteed.

When you get the medication, there will be an information leaflet inside; this will provide details of the range of side effects which have been noted in the past ranging from those which are quite rare to those which are far more common.

Finally, all pharmacists are highly trained on the subject of drugs and medication and will be able to give you advice about whether driving is contraindicated.



With our busy modern lives, it's all too easy to pop a prescription pill and then jump behind the wheel of the car without a second thought. However, the effects of medication can be very significant and lead to deadly consequences if an individual drives while under the influence. It may be unintentional but the outcome is the same, so it's essential to think twice before driving if you have taken any kind of drug, prescribed or otherwise.