Driving and medicines: which ones can affect you at the wheel?
Some medicines cause drowsiness, slow your reflexes or lower your blood sugar; knowing how to spot them lets you keep driving safely.
In short
- If your medicine box shows a red triangle with a car and the words ‘Conducción: ver prospecto’ (Driving: see leaflet), read the leaflet before you get behind the wheel.
- The ones most likely to affect you are medicines for anxiety and sleep, some antihistamines, antidepressants, antiepileptics, opioid painkillers and those that can lower blood sugar.
- The risk is higher in the first days of treatment, after a dose change and when combined with alcohol or other medicines that cause drowsiness.
- Spanish law allows you to drive on prescribed medicines, as long as you are fit to drive with due care.
Many commonly used medicines can affect driving because they cause drowsiness, slow your reflexes, blur your vision or lower your blood sugar. The quickest way to find out is to look for the driving pictogram on the box and read the leaflet; if you drive every day, tell your doctor so they can take it into account when choosing your treatment.
We explain which groups of medicines need most care, when the risk is highest and what the law says.
| What will you find in this article? |
How do you know whether a medicine may affect your driving?
Look at the box: medicines that can reduce your ability to drive carry a pictogram with a red triangle, a black car inside it and the words ‘Conducción: ver prospecto’. According to the AEMPS, the Spanish medicines agency, its purpose is to catch your attention so that you read the warning in the leaflet about its effects on people who drive or operate machinery.
The pictogram does not mean you are banned from driving, but that you need to find out more. In the leaflet, look for the section ‘Driving and using machines’. If you still have doubts, ask the pharmacist when you collect the medicine; you will find more ideas in what to ask your pharmacist about a new medicine.
Which medicines can affect driving?
The magazine of Spain's Directorate General for Traffic (DGT) lists, among others, medicines for insomnia, anxiety, psychosis, depression, epilepsy, Parkinson's, pain, allergy, colds and some eye drops. Not every medicine in each group has the same effect, which is why the leaflet for each one is your reference.
| Group | Possible effect when driving | What to do |
|---|---|---|
| Anxiolytics and sleeping tablets (such as benzodiazepines) | Drowsiness, reduced attention and slower reflexes | Avoid driving in the first days or after a dose change, as your doctor advises |
| Some antihistamines | Drowsiness, especially with alcohol | If yours carries the pictogram, ask about alternatives that cause less drowsiness |
| Antidepressants | Drowsiness and slowness, more so at the start | Follow your doctor's advice in the early stages |
| Opioid painkillers and muscle relaxants | Drowsiness and dizziness | Do not drive if you notice their effects |
| Insulin and some oral diabetes medicines | Hypoglycaemia (low blood sugar) | Check your glucose before driving and keep carbohydrates in the car |
| Some eye drops | Temporary blurred vision | Wait until you can see clearly |
According to the DGT, all insulins carry the pictogram on their packaging, while for oral diabetes medicines it depends on the drug or combination.
When is the risk highest?
The risk increases when you start a treatment, when the dose changes and when several medicines that cause drowsiness are combined or alcohol is added. For benzodiazepines, the DGT recommends avoiding driving for 6 to 8 days at the start of treatment or after a change of medicine or dose.
- Alcohol: it increases the drowsiness caused by many medicines. Read alcohol and medication: what you need to know.
- Polypharmacy: taking several medicines together increases the chance of interactions and side effects.
- Tiredness or lack of sleep: if you are tired and take sedating medicines, the DGT advises against driving.
- Self-medication: a cold remedy or an antihistamine bought without a prescription can also cause drowsiness.
If you feel drowsy, weak or your vision is blurred, do not drive and speak to your doctor.
What does the law say about driving on medication?
Spain's Traffic Act prohibits driving with drugs present in the body, but excludes substances used on medical prescription and for therapeutic purposes, as long as the driver is fit to drive with due care. In other words, taking a prescribed medicine is not prohibited, but if it affects you and you are not fit to drive, the exception does not protect you.
In practice: follow the dosing you have been given, do not increase the dose on your own, do not mix it with alcohol and, if you drive often, explain your timetable to your doctor so they can choose the medicine that interferes least, as the DGT recommends.
A practical example: Luis starts a treatment for sleep
Take the case of Luis, 54, a sales representative who drives every day to visit clients. He has been sleeping badly for weeks and his doctor suggests a medicine for insomnia for a short period.
Luis tells his doctor that he drives every day first thing in the morning. The doctor takes this into account when choosing the medicine and explains what to do in the first few days. At home, Luis sees the pictogram on the box, reads the driving section of the leaflet and arranges those days so he does not drive. He avoids alcohol and, if he feels drowsy one morning, he leaves the car and lets his clients know. At his next check-up he explains how it has gone.
How can IMA Health help you?
Taking your medication at the same time each day helps you know when you may notice its effects most. With IMA Health, a specialised pharmacy prepares your medicines organised by day and time, and the pharmacist is available to answer your questions about dosing.
We also coordinate with the pharmacy, deliver your medication to your home and provide personalised follow-up. You can see the details in the IMA Health service.
Sources
- AEMPS: Medicines and driving pictogram (in Spanish)
- DGT magazine: Benzodiazepines and driving, the tip of the iceberg (2024, in Spanish)
- DGT magazine: A dangerous combination, medicine interactions (2021, in Spanish)
- DGT magazine: Diabetes medicines and driving (2014, in Spanish)
- BOE: Royal Legislative Decree 6/2015, Traffic and Road Safety Act (article 14, in Spanish)
This article is for information only and does not replace advice from your doctor or pharmacist.