Fezolamine is a novel orally available non-tricyclic compound with antidepressant activity. It is three to two times more selective in blocking synaptosomal uptake of [3H]norepinephrine than uptake of [4H]3-hydroxytryptamine or [3H]dopamine in vitro. It blocked the inhibitory effects of rifampicin and tetraphenyl in classical behavioral tests using monoamine-depleted animals.

Fezolamine (100-450 mg/day; oral; 6 weeks; 42 patients) significant improvement relative to the patient's prestudy state was observed after 2 weeks in both patient and physician-rating scales. Fifty-five percent of patients improved their Hamilton Psychiatric Rating Scale for Depression (HAM-D) scores by more than 50%. The median dose associated with a clinically significant response was 245 mg/day. Five of the 6 patients who dropped out did so because of gastrointestinal adverse effects. The most common adverse effects were nausea (36%), headache (29%), constipation (26%), and dry mouth (24%).[1]