Dose related effects of trimipramine on psychomotor function, memory, and autonomic nervous system activity in healthy volunteers

The effects of single doses of trimipramine, a tricyclic antidepressant (25, 50 and 100 mg) and placebo on psychomotor performance, memory, haemodynamics, pupil diameter and salivary volume, were assessed in 12 normal volunteers. All subjects received each of the four treatments, at weekly interval, according to a double‐blind cross‐over Latinsquare design. Treatments effects were monitored using a battery of tests including critical flicker fusion (CFF), choice reaction time (CRT), subjective ratings of mood and memory tasks before, and 3 and 8 hours following medication. Supine standing blood pressure, pupil diameter and salivary volume were recorded at the same times. Compared to placebo, trimipramine impaired both subjective and objective measures in a dose‐related manner, with 25 mg affecting some subjective ratings and CFF, and 100 mg impairing most objective and subjective evaluations, except memory and haemodynamic variables. Pupil diameter was reduced by 50 and 100 mg trimipramine, whereas salivary volume was affected only by the highest dose studied. In conclusion, the sedative effects of trimipramine appeared dose‐related. No amnesic effect could be evidenced, at the doses studied. Changes in autonomic nervous system activity have been shown on pupil diameter and salivary secretion.