Aptazapine
Aptazapine (CGS-7525A) was a tetracyclic antidepressant developed in the 1980s. Aptazapine had noradrenergic and specific serotonergic activity. It antagonised α2 adrenergic receptors approximately 10 times more effectively than mianserin, antagonised 5-HT2 receptors, agonised H1 receptors, and did not affect reuptake of serotonin or norepinephrine. Although Aptazapine reached clinical trials, it was never marketed.