Effects of zimeldine, mianserin and amitriptyline on psychomotor skills and their interaction with ethanol a placebo controlled cross-over study.

13 healthy volunteers participated in a double-blind, four-period, cross-over study. In each period, the trial drugs (placebo, zimeldine, amitriptyline and mianserin) were given in fixed dosages for 8 days; amitriptyline 10-50 mg twice daily, mianserin 10-30 mg twice daily and zimeldine 200 mg once daily. Ethanol 1 g/kg bodyweight was drunk 2 hours after drug intake on Days 1 and 8 of each period, the latter being separated by a 2 week wash-out period. Ratings of subjective feelings and side effects, and performance tests were done on Days 1 and 8 of each period before, 1.5, 3 and 4.5 h after drug intake, i.e. 2 of the tests were performed under the influence of ethanol. Mianserin decreased critical flicker frequency, slowed reactions under discriminative stimulation and tended to cause nystagmus, but only on Day 1 (after the first 10 mg dose). Amitriptyline impaired coordination on Days 1 (after the initial 10 mg dose) and 8, and lowered the flicker threshold on Day 8 at "steady state" (after the 50 mg morning dose). Both these antidepressants were felt to be sedative, especially in the initial phase of the treatment, and they interacted additively with ethanol. No impairment of psychomotor skills was associated with zimeldine, only a subjective sedative effect of the 200 mg dose was seen on Day 1. Zimeldine did not enhance the effects of ethanol; it even showed some antagonism of ethanol-induced body sway in the standing steadiness test. In contrast to amitriptyline and mianserin, zimeldine was regarded as not harming psychomotor skills, and as not having any observable interaction with ethanol.