Effects of amitriptyline 50 mg, desipramine 100 mg, and zimelidine 200 mg alone and in combination with ethanol 0.8 g/kg were investigated in healthy, male volunteers. Amitriptyline increased body sway and impaired tracking as well as information processing. It had an additive deleterious pharmacodynamic interaction with ethanol. Desipramine and zimelidine were free of adverse effects on performance and did not have significant interactions with ethanol. The dose of ethanol used in the present study did not inhibit biotransformation of the antidepressants.