Anxiolytic effects of acebutolol and atenolol in healthy volunteers with induced anxiety.

Acebutolol (400 mg once daily), atenolol (100 mg once daily) and placebo were self administered to 12 healthy male volunteers in a double-blind crossover study. Each drug treatment was administered for 4 days so that subjects' plasma levels of the drug were at steady state. Subjects were tested on the 4th day. On each of the 3 test days subjects underwent an anxiety induction procedure involving both easy and difficult versions of the Stroop test and syntactic reasoning. Measures of state anxiety were taken during the difficult task, an easy version of the task and after a period of quiet relaxation. High, medium and low levels of anxiety corresponded to the three levels of task difficulty. Highly significant differences were exhibited in state anxiety between high, medium and low anxiety induction procedures with both Stroop test and syntactic reasoning. This was shown by highly significant main effects for task difficulty with both tasks. There was no significant anxiolytic action of either acebutolol or atenolol when compared to placebo (there were no drug effects or any interaction of drugs with task difficulty). There were no significant drug effects upon any of the cognitive test measures. Overall, there was no evidence of either anxiolysis or sedation with either of these two relatively hydrophilic drugs.