The emergence of new antidepressants for clinical use: Agomelatine paradox versus other novel agents

This study was designed with the rational aim of discussing the emerging antidepressant agents that are likely to bring positive landmark, tremendous improvement and significant impact to the management of patients with depression disorders. It also elaborates on the Agomelatine paradox vis-a-vis the other novel antidepressant agents. The emerging antidepressants are: selective monoamine oxidase inhibitors (MAOIs) such as bifemelane, pirlindole, toloxatone, selegiline, rasagiline and safinamide; serotonin-norepinephrine reuptake inhibitors (SNRIs) such as ansofaxine, nefopam and levomilnacipran; norepinephrine reuptake inhibitors (NRIs) such as Reboxetine, viloxazine, teniloxazine (also known as sulfoxazine or sufoxazine), and atomoxetine; Vilazodone (a serotonin 5-HT(1A) autoreceptor partial agonist with serotonin reuptake inhibition [SPARI]); Vortioxetine (a serotonin receptors antagonist with serotonin reuptake inhibition [SARI]); atypical antipsychotics such as olanzapine, quetiapine, risperidone, lurasidone, aripiprazole and brexpiprazole; N-methyl-d-aspartate (NMDA)-glutamatergic neurotransmission system blockers such as ketamine, CP-101,606 (traxoprodil), GLYX-13 (rapastinel), NRX-1074 (Apimostinel) and Riluzole. While Agomelatine (a melatonergic MT(1) and MT(2) receptors agonist and a selective serotonergic 5-HT(2B) and 5-HT(2C) receptors antagonist [MASSA]) remains a paradoxical agent that doesn't fit into any of the currently available classes of antidepressant agents and its pharmacological properties also deemed it unfit and inappropriate to be classified into another separate novel class of antidepressants contrary to the reports published in previous reference literatures. Lastly, this review remarkably advocates for the incorporation of the atypical antipsychotics and NMDA-glutamatergic ionoceptor blockers as new member classes of the antidepressant agents because of their clinically significant roles in the management of depression disorders.