The effects of challenge with pentobarbitone and pentobarbitone/alcohol, on psychomotor performance in tests with examine aspects of driving ability of subjects who have received subchronic doses of pentobarbitone.

Subjects were given a capsule of pentobarbitone (100 mg) or an identical placebo capsule to be taken nightly for seven nights. Their performance in psychometer tests relating to driving skills was monitored before drug administration and after a challenge dose of pentobarbitone (100 mg or 0 mg), which was given either alone or in combination with a dose of alcohol. On Day 8, the performance of subjects was again tested before and after doses of pentobarbitone, with or without alcohol. Venous blood samples were used to measure pentobarbitone and breath analysis was used to measure alcohol concentration. Various trends were found, implying that drivers who receive therapeutic doses of pentobarbitone may be significantly impaired during the first week of treatment and that the effects of a modest dose of alcohol are likely to be exacerbated by pentobarbitone treatment. (A)