Advice with driver on his medication. Antihistamines, analgesics and antitussives

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Drug consumption without medical control is a serious problem.

Over-the-counter drugs are increasingly is dispensed as indicated by non-qualified subjects, who many times do not know the diseases and their treatment

Drugs are also consumed with medical prescription but to criterion of the patient himself without asking their physician.

  • The physician should advise against driving, if the drug:
    • Causes difficulties in vision, blurred vision, reduction of visual field, double vision, or dry eye.
    • It leads to somnolence or difficulty in the concentration and attention.
    • It enhances slow reactions in case of unexpected events in traffic, or makes it difficult to maintain the car in its lane, frequently invading the contrary road.
    • It causes that driving is carried out without the adequate environment control, and they do not know how they have arrived at their destination.
  • Some groups of drugs that hinder the ability to drive

H1 antihistamines

Antihistamines usually involve serious contraindications to drive, such as somnolence, depression, reduction of alertness and delayed time to reaction.

These effects are often unknown by the affected patient self-medicating.

They ca also cause anxiety, insomnia, visual disturbances, dyskinesia, paresthesia and hallucinations.

First-generation antihistamines of the family of dexchlorpheniramine can cause lightheadedness, sedative effect and hypotension in those over 60 years of age.

It is recommended not to fulfill activities requiring maximum attention such as driving during the treatment.

For years there are “new antihistamines” such as astemizole, loratadine, ebastine, and terfenadine among others, with very low sedative effects.

Antihistamines such as loratadine at daily doses of 10 mg do not cause sedation, and can be used when driving.

However, they show a serious risk when mixed with alcohol, because they cause somnolence and increase the time to reaction, even at low doses.

The patient with special sensitivity to the drug who notices side effects should notify it to his physician. Accordingly, the patient should be warned when prescribing it.

H2 antihistamines

They generally show a low risk for driving cars.

They occasionally cause dizziness, fatigue, somnolence, and difficulty in concentration.

Cimetidine, ranitidine, and nizatidine inhibit alcohol metabolism with high blood alcohol levels for longer time, and the patient should be warned also for their interference with other drugs.

Opium alkaloids

Codeine, dimemorfan phosphate, and dextromethorphan hydrobromide can impair the mental and physical ability required to drive cars, due to their central nervous system effects.

Its effects are evidenced as sedation, dizziness, decreased concentration and decision-making, and some euphoria.

Codeine has antitussive, analgesic and slightly sedative effects, and can cause nausea, vomiting, constipation and somnolence.

Its effect is potentiated with other narcotic analgesics such as buprenorphine, morphine, fentanyl, tramadol, pentazocine, thyldin, pethidine, and also, with antipsychotics, anxiolytics, neuromuscular blockers and alcohol.

Nasal decongestants

In presentation, with sympathomimetic such as phenylephrine, with antiallergics such as sodium cromoglycate, or with corticoids of budesonide type.

They do not interfere with driving.


Ambroxol, carbocysteine, acetylcysteine, and bromhexine.

They do not interfere with driving.

Advice with medication and influence on driving

  • Follow the instructions of the physician with regard to schedules and treatment time. Any effect or change noticed due to the drug should be notified to the physician as soon as possible.
  • Do not used medicines of other people, believing that they suffer the same.
  • Do not self-medicate or use drugs continuously without medical control.
  • Taking alcohol and drugs together can potentiate the adverse events, such as sedation and loss of reflexes
  • Driving under the effects of substances that reduce psychophysical conditions involves a significant risk for the driver, companions, and the other drivers.
  • Do not hide in the physical examination of drivers the drugs and adverse events. Favorable medical reports should be first provided for obtaining the driving license or its extension.
  • Patients under the effects of narcotic analgesics should be advised against driving.
  • The narcotics used as antitussive require very lower dosages than analgesics; however, the patient should be warned of the risk of increasing the drug dose on his own in terms of amount and number of doses and of the possible side effects that will reduce the safety on driving.