Vilazodone N-Oxide-d4 is the isotope labelled analog of Vilazodone N-Oxide (V265020); a metabolite of Vilazodone (V265000) which is a combined serotonin specific reuptake inhibitor (SSRI) and 5-HT1A receptor partial agonist currently under clinical evaluation for the treatment of major depression. Also an antidepressant.