Mirtazapine: a new drug class of antidepressant

Mirtazapine (Remeron) is a novel antidepressant with a unique mode of action. It has been recently approved by the U.S. Food and Drug Administration (FDA) for treatment of depression. It is a unique antidepressant due to its specificity of effects on noradrenergic and serotonergic systems. Mirtazapine (figure 1) is a tetracyclic and belongs to the piperazinoazepine. It is (structurally) analog of mianserin, an antidepressant not approved by the FDA, but there are considerable differences in their biological properties (1-4). In addition to mirtazapine antidepressant activity, there are some data indicating that it may also possess anxiolytic activity and improve sleep patterns associated with depression probably due to its selective rapid eye movements (REM), connoting the dream phase during sleep with sleep suppressing effect (3,5)