Clinical profile and serum concentration of viloxazine as compared to amitriptyline

The antidepressive effect of viloxazine (300 mg/d) was investigated during three weeks in 41 patients with depressive syndromes requiring drug-treatment against amitriptyline (150 mg/d), using a controlled double-blind design. Viloxazine differs from amitriptyline by selective inhibition of norepinephrine re-uptake, whereas amitriptyline acts also on serotonin re-uptake. Psychopathological changes were documented by means of the Hamilton Depression Rating Scale, the Bf-S (v. Zerssen), the AMDP-System, and videotaped recordings. Besides routine clinical-chemical tests, the serum concentrations of viloxazine and partly of amitriptyline were determined. Repeated EEG-recordings were evaluated by spectral analysis. The number of global responders and non-responders -- defined according to the final HDRS-scores -- was equally distributed between the two drug-groups. The AMDP-evaluation suggests that viloxazin has a somewhat more marked and more rapid effect on symptoms of retardation, whereas amitriptyline acts predominantly on depressive mood, disturbances of sleep and vital feelings. The EEG-profile of both drugs was similar to the spectral changes seen under tricyclic antidepressants, through only the viloxazine-induced changes reached statistical significance on the 10th and 20th day, the variability of the EEG-recordings being greater in the amitriptyline group. The viloxazine blood levels showed a remarkably low inter- and intraindividual variance. Steady state was reached at day 5 at the latest. Amitriptyline serum concentrations still increased between the 10th and the 21st day. The average blood concentration of viloxazine was higher in the responder- than in the non-responder-group.