Advancing past ketamine: emerging glutamatergic compounds for the treatment of depression.

Changes in glutamate-related brain plasticity may underlie depression, leading researchers to explore components of the glutamate synapse as targets for faster-acting antidepressants. The NMDA receptor blocker ketamine and its S-enantiomer esketamine already show rapid antidepressant effects. This review examines other glutamatergic rapid-acting antidepressants beyond (es)ketamine that have meaningful clinical trial data, including arketamine, esmethadone, nitrous oxide, and other glutamate receptor modulators. Substances successful only in preclinical studies or case reports are discussed marginally. The authors aim to highlight glutamatergic modulation's critical role in advancing antidepressant therapy, potentially improving clinical outcomes and reducing depression's burden through faster therapeutic effects.

Study at a glance

Abstract

Changes in glutamatergic neuroplasticity has been proposed as one of the core mechanisms underlying the pathophysiology of depression. In consequence components of the glutamatergic synapse have been explored as potential targets for antidepressant treatment. The rapid antidepressant effect of the NMDA receptor antagonist ketamine and subsequent approval of its S-enantiomer (i.e. esketamine), have set the precedent for investigation into other glutamatergic rapid acting antidepressants (RAADs). In this review, we discuss the potential of the different glutamatergic targets for antidepressant treatment. We describe important clinical outcomes of several key molecules targeting components of the glutamatergic synapse and their applicability as RAADs. Specifically, here we focus on substances beyond (es)ketamine, for which meaningful data from clinical trials are available, including arketamine, esmethadone, nitrous oxide and other glutamate receptor modulators. Molecules only successful in preclinical settings and case reports/series are only marginally discussed. With this review, we aim underscore the critical role of glutamatergic modulation in advancing antidepressant therapy, thereby possibly enhancing clinical outcomes but also to reducing the burden of depression through faster therapeutic effects.