Esketamine Nasal Spray For Treatment-Resistant Depression

Esketamine is the S-isomer of racemic ketamine. Esketamine targets the N-methyl-D-aspartate receptor, an ionotropic glutamate receptor in nerve cells. However, the mechanism by which esketamine exerts its antidepressant effect is unknown. It is currently approved for patients with treatment-resistant depression or major depressive disorder with acute suicidal ideation or behavior. Treatment-resistant depression is chronic depression that does not improve despite the adequate use of multiple antidepressants. The poor response to multiple antidepressants limits additional treatment options. Patients with major depressive disorder who have active suicidal ideation with intent constitute a psychiatric emergency as the time between the onset of suicidal ideation and suicide attempt is often very short. While standard antidepressants effectively treat depressive symptomatology, including suicidal ideation, these agents require 4 to 6 weeks to exert their full effect, limiting their utility in crisis situations.