Traffic Department warns the drivers about the side effects of certain medicines

It is known that almost all medicines have side effects. They might be something minor like a mild headache or even not affect you at all. However, when it comes to driving, one should be extremely careful. According to the Spanish Traffic Department, 5% of all the road accidents are due to the use of medication. Therefore, it puts your life and health (and that of others) in danger. It also states that 25% of all the medicines authorised by the Spanish Agency for Medication and Healthcare Products (AEMPS) can affect your driving by producing drowsiness or by slowing down your reflexes. If there is a risk of side effects that might affect your driving, you will find a special sign on your medication box. It is a warning red triangle with a black car on a white background inside. 
The danger of driving when taking certain medications increases even more as most drivers are not aware of the effects these drugs have on their driving abilities. Hence, the fundamental role that both the doctor and the pharmacist have is in informing the patient about what he is going to take. According to recent studies, receiving information about the effects of a given medication on driving reduces the annual accident rate by 45% for every 1,000 patients. In case of self-medication, this effect of prevention is, unfortunately, lost.
Groups of Medicines
Medicines

False Positive

Not only can these drugs put you and others in danger, they can also yield a false-positive result during a drug control test carried out by the police (Guardia Civil de Tráfico). The consequence of that is a fine of 1000€. Which would be quite unfair considering you did not know that your medication can alter your test results. Moreover, if you refuse to carry out the drug test, you might be subject to imprisonment. Prevention is better than cure, so always double-check with your doctor when you get the prescription. 

Non-Prescription Drugs

You should also watch out for the medicines you can get without a prescription. They can have the same adverse effects and equally score positive during a drug control test. Don’t forget either that they can interfere with other medication you are already taking and provoke an unexpected reaction in your body. To always be on the safe side, you should consult your GP before starting any treatment. The side effects that a drug can have are also subject to the quantities your doctor prescribes.

Alcohol 

If alcohol is added to the equation, everything gets more complicated. Not only does it have dangerous effects on one’s body per se, if alcohol consumption is also combined with taking one’s medications, the effects might be completely unexpected. Its metabolism involves two enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase. If a certain drug inhibits this process, unusual effects may occur in response to only a small intake of alcohol.