The Dangers of Driving Whilst Under Medication

17 March


Slower responses, impaired judgement...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 which can have the same effect but many people continue to drive, risking harm to both themselves and others.

Prescribed medication can be particularly potent and the effects can be similar, or worse, than drinking alcohol. Despite this, it's easy to overlook the perils associated with the use of medication and continue to drive whilst under the influence.

We take a closer look at the dangers of driving whilst under medication and the legal position if you are caught.

The law

The legal situation is far less explicit relating to drugs, but nevertheless you could easily find yourself on the wrong side of the law if you take medication and then drive.

The Road Traffic Act 1988, Section 4(1) and (2) specifies that any person attempting to drive in a public place whilst unfit through either drink or drugs shall be deemed to have committed an offence.

Unlike alcohol, there are no exact limits specified nor drugs named; for the purposes of this law both prescribed and illegal drugs are treated in the same way.

This law is in place to prevent those who are affected by medication from driving until they are fit to do so. If found guilty, the consequences will be similar to that of drink-driving, including future points on the licence and higher insurance premiums.

How will I know if I am affected?

Some drugs are more likely to cause side effects than others but it is very much an individual thing.

Not everyone suffers the same effects when given medication; two people given an identical drug can have contrasting consequences. For example, diazepam will normally have a very sedative effect but in a small number of cases, an individual will become hyperactive. There's simply no way of telling in advance how you will respond to a drug.

This is 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 until you start taking it so it's best to plan to stay away from the car until you get used to it.

Many drugs have an adverse effect when they are first taken but as the body adjusts, the side effects disappear. Therefore, just because you are unfit to drive when you first start taking a medication doesn't always mean it will be the case.

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 amongst 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 which 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 and don't make any plans to drive until you are sure you are safe to do so.

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 whilst under the influence. It may be unintentional but the outcome is the same therefore it's essential to always think twice before driving if you have taken any kind of drug, prescribed or otherwise.

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