Clinical utility of vilazodone for the treatment of adults with major depressive disorder and theoretical implications for future clinical use

BACKGROUND Vilazodone is the latest approved antidepressant available in the United States. Its dual mechanism of action combines the inhibition of serotonin transporters while simultaneously partially agonizing serotonin-1a (5-HT1A) receptors. This combined activity results in serotonin facilitation across the brain's serotonergic pathways, which has been termed by the authors as that of a serotonin partial agonist and reuptake inhibitor, or SPARI. OBJECTIVE The authors to review laboratory, animal model data, and human trial data to synthesize a working theory regarding the mechanism of antidepressant action of this agent and regarding its potential for additional indications. METHODS A MEDLINE and Internet search was conducted and the resultant evidence reviewed. RESULTS Vilazodone has randomized, controlled empirical data which has garnered it an approval for treating major depressive disorder. It combines two well-known pharmacodynamic mechanisms of serotonergic action into a novel agent. Although no head-to-head studies against other antidepressants are published, the efficacy data for vilazodone appears comparable to other known antidepressants, with associated gastrointestinal side effects similar to serotonin selective reuptake inhibitor and serotonin norepinephrine reuptake inhibitor antidepressants, but potentially with a lower incidence of sexual side effects and weight gain. DISCUSSION As a new option for the treatment of major depressive disorder, vilazodone, due to its unique SPARI mechanism of action, may hold promise for patients who cannot tolerate or have not responded to previous antidepressant monotherapies. Additionally, its use may extend to the treatment of other mental health conditions similar to those treated by serotonin selective reuptake inhibitors.