The Effects of Zimeldine and Amitriptyline on Car Driving and Psychomotor Performance

The development of an objective measure of car driving performance, brake reaction time (BRT), is described, and the effects of amitriptyline and zimeldine on this measure are compared in a placebo-controlled, acute, single dose, volunteer study. The effects of treatment on laboratory tests of critical flicker fusion (CFF) threshold, choice reaction time (CRT) and tracking accuracy and on self-assessments of sedation are also examined. At 2 hours post-treatment, amitriptyline produced a significant increase in brake reaction time when compared to both placebo and zimeldine. At 4 hours post-treatment, a significant reduction in "tracking accuracy" and a significant increase in CRT was observed after treatment with amitriptyline, while no such effects were seen with zimeldine. Measures of CFF threshold and self-ratings of sedation also revealed that amitriptyline produced a significant degree of sedation at 4 hours when compared to zimeldine and placebo. In contrast, zimeldine produced elevated CFF threshold, but did not affect self-ratings of sedation.