Drug side effects and selection of those with less impact in driving

Every drug administration involves the risk of causing an adverse reaction.

Many patients cannot recognize or identify the side effects of the new drug they start to take.

Hence, it is advisable that both the patient and his family members are informed at the beginning of any therapeutic regimen.

Many of the potential drug adverse reactions can decrease the ability to drive, and neither the driver nor his companions are aware of this.

It is estimated that near 10% of traffic accidents are due to wrong maneuvers by the driver, due to drug consumption that affect the ability to drive.

In the European Union, 10% of people dead or injured in traffic accidents had taken some type of psychoactive drug.

Nearly 30% of drivers are treated and, from these, over 64% takes two or more drugs at the same time.

Co-prescription of several drugs is important, for the interaction that can be established among them.

European and Spanish regulations define the labeling and the package leaflet of drugs for human use

The proposal to rate drugs in three levels based on their degree of influence on driving has been endorsed; therefore, we may choose that causing fewer adverse events when driving.

  • Category I: drugs likely to cause moderate effects on the ability to drive.
  • Category II: drugs likely to cause severe effects on the ability to drive.
  • Category III: drugs likely to cause very severe effects on the ability to drive.

Psychoactive drugs are the most dangerous.

Tranquilizers and sedatives reduce the time to reaction and the reflexes, and cause blurred vision and somnolence.

Stimulants enhance despising risk, violent driving, depression, and somnolence due to rebound effect.

Other potentially dangerous drugs are antihistamines, hypotensives, antitussives, antidepressants, cardiotonics, hypoglycemic, most anticonvulsants, anorexigens, antispasmodics and antiparkinsonians.

Anticholinergic effect: somnolence, dizziness, blurred vision, and headache.

  • Main drug side effects that can affect driving:
  • Sedative effect: reduction of alertness, slow reaction to unexpected events and somnolence.
  • Stimulation reactions: dizziness, tremor, muscle spasms, nervousness, tachycardia, irritability, and insomnia.
  • Neuropsychiatric effect: disorientation, dizziness, nystagmus, headache, depression, hallucinations, agitation, mental confusion, psychotic reactions, etc.
  • Extrapyramidal manifestations: seizures, agitation, lack of motor coordination
  • Ophthalmologic disorders: blurred vision, accommodation disorders, transient short-sightedness
  • Hearing disorders: tinnitus, buzzing sounds, hypoacusis
  • Circulatory disorders: hypotension, arrhythmia, heart arrest.

Recommendation on drug side effects

  • A clinical history should essentially outline if a patient drives, as driving is a daily activity in the community, and our patients should be in the best psychophysical conditions to do it, particularly those driving every day, professional drivers or elderly drivers.
  • Therapeutic guidelines should be established that have very few adverse events on driving, not exceeding the recommended doses, particularly in the elderly and considering the possibility of divided doses, at night or after car travels.
  • The physician knows the reasons for taking the drug, and should assess the specific effects of the recommended dosage.
  • In principle, the drugs prescribed improve the clinical condition of the patient optimizing his ability to drive, but in some cases the side effects lead to an impaired psychomotor performance.
  • If possible, the topical rather than the oral route will be used, which prevents many systemic adverse reactions, as is the case of antihistamines.
  • Physicians should always ask for the drugs taken by the patient and assess the possible interference with the drugs prescribed, the psychomotor performance and the ability to drive.
  • Alcohol interaction with multiple drugs increases the risk of psychomotor and cognitive function impairment and increases the risk of accident. The patient should be warned.

Drug selection for driver patients les affecting the ability to drive

  • Antihistamines: Azelastine, astemizole, loratadine, terfenadine, ebastine
  • Antidepressants: Fluoxetine, fluvoxamine, moclobemide, paroxetin.
  • Hypnotics: Zopiclone, zolpidem, temazepam, lormetazepam.
  • Tranquilizers: Buspirone.
  • Anticonvulsants: Lamotrigine, vigabatrin.
  • Antihypertensives: Calcium antagonists, conversion enzyme inhibitors.

Physicians are responsible for the proper prescription and treatment regimens and for providing the driver patient the adequate preventive information for safety in driving.

The better health agent is the physician. The advice given to the patient and to his relatives about the drugs prescribed will be essential for the prevention of traffic accidents.