Effects of single doses of alprazolam and alcohol alone and in combination on psychological performance

The effects of alprazolam l mg alone and in combination with 0·5 g/kg of alcohol for males and 0·42 g/kg for females were examined on a range of psychological tasks 90 and 180 min post‐drug (45 and 135 min post‐alcohol). Forty‐eight healthy volunteers were assigned randomly to four independent groups who received: alprazolam and placebo drink, alprazolam and alcohol, placebo capsule and alcohol, placebo capsule and placebo drink, respectively. Alprazolam caused subjective sedation, unsteadiness, dizziness and physical tiredness and impaired performance on all tasks. Alcohol caused similar subjective effects but little objective impairment. The effects of the combination were generally no greater than predicted from the sum of the single effects.