Vilazodone

Vilazodone (marketed as Viibryd) is an SSRI antidepressant developed by Clinical Data for the treatment of major depressive disorder. The chemical compound was originally developed by Merck KGaA (Germany).^[1] By 2009 two phase III clinical trials with positive results had been completed.^[2] Vilazodone was approved by the FDA for use in the United States to treat major depressive disorder in 10 mg, 20 mg, and 40 mg doses on January 21, 2011.^[3][4][5]

Pharmacology

Vilazodone acts as a serotonin reuptake inhibitor (IC₅₀ = 0.5 nM) and 5-HT_1A receptor partial agonist (IC₅₀ = 0.2 nM; IA = ~60-70%).^[6][7] It has negligible affinity for other serotonin receptors such as 5-HT_1D, 5-HT_2A, and 5-HT_2C.^[6][7]

Partial agonism of the 5-HT_1A receptor is a relatively novel mechanism of action and is also shared by the anxiolytic buspirone (Buspar), and the atypical antipsychotic / antidepressant aripiprazole (Abilify).

Efficacy and tolerability

According to an eight-week, randomized, double-blind, placebo-controlled trial, vilazodone was reported to elicit an antidepressant response after one week of treatment. After eight weeks, subjects assigned to vilazodone experienced a significantly higher response rate than the group given placebo. At a dose of 40 mg per day, it is considered to be well tolerated and reported adverse effects ranged from mild to moderate in intensity; side effects included diarrhea, nausea, and somnolence.^[8] In contrast to other SSRIs currently on the market, initial clinical trials showed that vilazodone did not cause significant weight gain or decreased sexual desire/function as with many other antidepressants, which often cause people to abandon their use.^[3] However, FDA staff called these claims into question in a September 2011 article that concluded "it is unknown whether [vilazodone] has any advantages compared to other drugs in the antidepressant class." ^[9]

See also

References