aptazapine

Aptazapine is a tetracyclic antidepressant that was investigated as a potential treatment for depression. It is structurally and pharmacologically related to mirtazapine, another tetracyclic antidepressant, but was never marketed. Aptazapine acts primarily by antagonizing central presynaptic α2-adrenergic inhibitory autoreceptors and heteroreceptors, which increases central noradrenergic and serotonergic activity. It also antagonizes serotonin 5-HT2 and 5-HT3 receptors, histamine H1 receptors (contributing to sedative effects), peripheral α1-adrenergic receptors (which may cause orthostatic hypotension), and has moderate antimuscarinic activity. Despite its development as an antidepressant, it did not reach the market.