Drug interaction on psychomotor skills related to driving: Diazepam and alcohol

Summary The effects of combinations of diazepam (5 and 10 mg) and alcohol (0.5 and 0.8 g/kg) on skills related to driving were studied in 200 volunteer students. A choice reaction test and two co-ordination tests were employed, one of which was carried out at a fixed speed, and in the other the speed was chosen by the subject himself. — On their own these drugs either did not affect or even slightly improved the skills measured, but their various combinations definitely impaired the subjects' performances. This effect was greatest before the peak levels of blood alcohol were reached. — The combination of these drugs is considered dangerous for driving. The practical effect of taking one of these drugs on its own is more difficult to assess.