Effect of atenolol on car drivers in a prolonged stress situation.

The effects of atenolol were investigated in car drivers participating in an amateur car rally. Atenolol or placebo were administered to two groups of 20 crews (driver and assistant) in this double-blind randomized trial. When compared with placebo, there was no deterioration in subjective appraisal of alertness and reaction ability in subjects given atenolol, and stress symptoms were markedly reduced. When compared with previous experience, the incidence of improved subjective appraisal of general driving ability was higher with atenolol (30 reports) than with placebo (5 reports). Furthermore the incidence of unchanged or worsened driving ability was significantly higher (p less than 0.001) with placebo (34 reports) than with atenolol (9 reports). At the end of the rally (16 hours after administration) subjects receiving atenolol 50 mg had significant reductions in heart rate (p less than 0.001), diastolic pressure (p less than 0.01), and systolic pressure (p less than 0.01) when compared with placebo.