Medicines affecting the ability to drive

18 June 2019

Some medicines can make you feel sleepy, intoxicated and could affect your judgment, concentration and reaction. The effect of taking these medicines is comparable to having a blood alcohol level and could therefore increase the risk of accidents considerably.

You should avoid driving or operate dangerous machinery while you are influenced by medicines affecting the ability to drive.

The Danish Medicines Agency labels medicines that significantly impair the ability to drive with a red warning triangle.

But be aware that some medicines without a red warning triangle could still affect your ability to drive.

You can find more information about how the medicine you take affects your ability to drive and use machinery in the medicine’s package leaflet.

How strong is the effect of the medicine?

It depends on how much medicine you take. We cannot say for certain how you will react as people respond differently to medicine. Factors such as gender, age, weight and dose all play a part in how the medicine affects you.

Usually, the sedative effect is strongest in the beginning of treatment and when the dose is increased. If you start on a new medicine that has a red warning triangle, or the medicine’s dose is changed, it is important that you avoid driving until you know how you respond.

If you take more than one medicine, sometimes the sedative effect can increase.

Drugs affecting the ability to drive together with alcohol

If you take medicines with alcohol, the alcohol may increase the sedative effect of medicines affecting the ability to drive. Therefore never mix alcohol with a drug that affects the ability to drive. Even one single glass of beer or wine increases the sedative effect significantly.

Ask your doctor if you are unsure

You can get advice from your doctor about driving while you are on prescription medicines affecting your ability to drive.

If you start taking medicines with a warning triangle or medicines for psychiatric disorders, diabetes, or high blood pressure, check with your doctor if you shouldn't drive at all. Do so also if the dose of your treatment is changed.

Doctors have authority to issue a full or partial driving ban in relation to the prescribing of certain types of medicines.

When your doctor considers if you should or shouldn’t be driving, he or she consults guidelines prepared by the Danish Patient Safety Authority.

The Danish Patient Safety Authority advises practicing doctors, the police, other authorities and administrations in matters of medicines and road safety.

What happens if I am stopped by the police?

Sections 54-55 of the Danish Road Traffic Act provide that it is illegal to drive if the medicine you take affects your ability “to drive the vehicle in a completely safe manner”. Or if you have taken a medicine affecting the ability to drive without having a prescription.

If the police suspect you are driving with a medicine affecting the ability to drive in your blood, they can request you to take a blood or urine test or that you be examined by a doctor. The penalties are the same as for drunk driving.

Special requirements for certain occupational groups

Some drugs affecting the ability to drive are considered to be so dangerous by some industry organisations/employers that you are not allowed to take them while you work – even if the medicine is not labelled with the red warning triangle. If you're not sure whether this is the case for your medicine, please check this with your industry organisation.

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