Comparative Study of the Effects of Captodiamine and Lorazepam on Car Driving Ability

Abstract

Objective: To compare the effects of lorazepam, a benzodiazepine-type anxiolytic agent, with those of captodiamine, a non-benzodiazepine anxiolytic agent, on vigilance and on driving behaviour. Design: Randomised, double-blind, crossover trial. Study Participants: Sixteen healthy male volunteers, aged 29 to 44 years, medically qualified to drive, holding a driving licence for more than 5 years, and driving more than 15 000km per year. Intervention: Lorazepam 0.5mg in the morning and at lunchtime, 1mg at bedtime, for 7 days; captodiamine 50mg in the morning, at lunchtime and at bedtime, for 7 days. Outcome Measures: Principal criterion: driving test on a 900m circuit with assessment of the number of errors resulting from clumsiness, excessive inhibition and disinhibition. Other criteria: psychometric tests (visual and auditory reaction times, tremometric test) and measurement by visual analogue scales of the degree of internal stress, anxiety, drowsiness and reduction of physical and mental capacity. All measurements were made before and after 7 days of treatment. Results: During the driving test a reduction in the number of errors resulting from clumsiness and disinhibition was observed with captodiamine, whereas an increase in the number of errors was seen with lorazepam (p < 0.001). A trend towards a shortening of auditory reaction time was noted in favour of captodiamine (p < 0.10). The reduction in internal stress was significantly greater with lorazepam compared with captodiamine (p < 0.05). Atendency to drowsiness was noted with lorazepam (p < 0.10). No other trend or significant difference was observed between the two drugs. Conclusion: Compared with lorazepam, captodiamine improved the concentration and dexterity of individuals when driving, without inducing a tendency to drowsiness.