A comparison of the pharmacodynamic profiles of nomifensine and amitriptyline in normal subjects.

1 Six healthy male volunteers participated in a double-blind placebo crossover comparison of the pharmacodynamic profiles of single oral doses of 75 mg nomifensine and 50 mg amitriptyline. 2 Nomifensine treatment did not influence salivary flow and did not significantly affect psychomotor performance (critical flicker fusion, pursuit rotor and reaction time): in addition nomifensine had no significant effect on subjective measurements of sedation and concentration. 3 By contrast, amitriptyline treatment significantly reduced salivary flow and was associated with significant sedation and reduced concentration: significant changes in psychomotor performance were also noted. 4 Plasma concentrations of amitriptyline and nomifensine were measured at 2 h. The respective median concentration values were 55.0 ng/ml and 52.0 ng/ml. 5 Ex vivo platelet amine uptake of dopamine (DA) and 5-hydroxytryptamine (5HT) was measured 2 h after each treatment. Both nomifensine and amitriptyline treatment significantly inhibited DA uptake to a similar extent. Amitriptyline treatment additionally inhibited 5-HT uptake.