Effect of active metabolites of chlordiazepoxide and diazepam, alone or in combination with alcohol, on psychomotor skills related to driving.

The interaction of the main metabolites of diazepam and chlordiazepoxide with alcohol was measured in two double-blind crossover subacute experiments on 40 healthy young volunteers. The drugs were administered for 2 weeks each. The variables measured were choice reaction time and accuracy, eye-hand coordination, divided attention, flicker fusion, proprioception, and nystagmus. ChL, MO and O significantly enhanced the alcohol-induced impairment of psychomotor skills whereas DMD did so only exceptionally on some subjects in the choice reaction test. It is concluded that the diazepam-alcohol interaction on psychomotor skills is mainly due to the parent compound. No correlations between the serum levels of the agents and the changes of performance were found.