mirtazapine
n. an antidepressant whose mechanism of action differs from that of most other antidepressants. It is considered to be a multifunctional antidepressant in that two separate actions result in increased neurotransmission of norepinephrine and serotonin. By binding to presynaptic α2-adrenoreceptors (see alpha-adrenergic receptor; autoreceptor), it enables continued release of norepinephrine from presynaptic neurons. It also acts as a serotonin agonist at postsynaptic 5-HT1 receptors. Other actions of mirtazapine include potent antagonism of other serotonin and histamine receptors, but it does not inhibit the reuptake of serotonin or norepinephrine. Sedation and weight gain are common adverse effects of mirtazapine, probably due to its potent ability to block the histamine H1 receptor. Unlike many other antidepressants, in most patients mirtazapine does not cause sexual dysfunction.
Rarely, agranulocytosis has been associated with its use. U.S. trade name: Remeron.