Efficacy of mirtazapine in clinically relevant subgroups of depressed patients.

Mirtazapine is a noradrenergic and specific serotonergic antidepressant (NaSSA) with a novel mode of action that differs from other antidepressants that are currently available. Clinical trials have demonstrated it to have good antidepressant efficacy and excellent tolerability. Analysis of the results of placebo-controlled trials in moderately or severely depressed patients have shown mirtazapine to be effective in clinically important subgroups of depressed patients, particularly anxious patients, patients with sleep disturbance, retarded patients, and agitated patients. The efficacy and tolerability of mirtazapine are attributable to its pharmacological profile. It is likely that the overall antidepressant activity arises from its dual action, enhancing both noradrenergic and 5-HT1 receptor-mediated serotonergic neurotransmission, while the anxiolytic and sleep-improving properties of mirtazapine are attributable to the specific blockade of 5-HT2 and 5-HT3 receptors.