The consumption of tranquilizers has increased throughout the 1960s. At present more than 100 million prescriptions of tranquilizers are written annually in the U.S.A. In a Norwegian study diazepam was found in the blood of 18% of people injured in traffic accidents. Other epidemiological studies have demonstrated an increased traffic accident risk to be associated with the use of tranquilizers. The combined use of tranquilizers and alcohol, which is common among patients, increases one's accident risk from that due to either agent alone. Laboratory studies concerning the effects of tranquilizers on skills related to driving have demonstrated impaired information processing capacity and eye-hand coordination due to these agents. Neuroleptics impair information processing especially at the onset of the treatment whereas the hazards of benzodiazepines become evident during long term treatment. Most of the tranquilizers increase the deleterious effects of alcohol on skills related to driving. Particularly strong is the interaction between diazepam and alcohol. At present the best countermeasure against accidents caused by tranquilizers seems to be easily available information about the effects of drugs on driving. At the onset of treatment with a neuroleptic or during long term treatment with a high dose of benzodiazepines, one should cease driving.
Abstract