Vilazodone Hydrochloride Tablets (Viibryd)
Pharmacology Update
Vilazodone Hydrochloride Tablets (Viibryd)
By William T. Elliott, MD, FACP, and James Chan, PharmD, PhD. Dr. Elliott is Chair, Formulary Committee, Northern California Kaiser Permanente; and Assistant Professor of Medicine, University of California, San Francisco. Dr. Chan is Pharmacy Quality and Outcomes Manager, Kaiser Permanente, Oakland, CA. Drs. Elliott and Chan report no financial relationship to this field of study.
A new antidepressant that combines selective serotonin reuptake inhibition with partial agonism of the 5-HT1A receptor has been approved by the FDA. Vilazodone is marketed by Trovis Pharmaceuticals as Viibryd™.
Indications
Vilazodone is indicated for the treatment of adults with major depression disorder.1
Dosage
The initial dose is 10 mg once daily for 7 days, then 20 mg once daily for 7 days, and increased to 40 mg once daily. The tablets should be taken with food to ensure adequate drug absorption.1 The dose should be reduced if given concomitantly with a strong CYP3A4 inhibitor (e.g., ketoconazole). The concomitant administration with a CYP3A4 inducer may reduce the effectiveness of vilazodone.1 Vilazodone may increase the level of drugs metabolized by CYP2C8.1
Potential Advantages
Vilazodone appears to have minimal effect on sexual dysfunction and does not prolong the QTc interval.2
Potential Disadvantages
The absorption of vilazodone is highly affected by food. Taking the drug under fasting condition reduces the plasma level by approximately 50% compared to the postprandial condition.1 The most common adverse reactions associated with vilazodone (vs. placebo) are diarrhea (28% vs. 9%) and nausea (23% vs. 5%).1
Comments
Vilazodone is a dual-acting serotonergic antidepressant. The efficacy was shown in two 8-week, randomized, double-blind, placebo-controlled studies in adults with major depressive disorder.1,2 Study participants were randomized to vilazodone (titrated up to 40 mg daily over 2 weeks; n = 435) or placebo (n = 433). The primary efficacy endpoint was the mean change from baseline to week 8 on the Montgomery-Asberg Depression Rating Scale (MADRS). The least square mean differences from placebo were -3.2 (95% confidence interval [CI], -5.2 to -1.3) for Study 1 and -2.5 (95% CI -4.4 to -0.6) for Study 2. A statistically significant difference was observed at week 1.2 The most common adverse effects were diarrhea and nausea. These were generally mild to moderate in intensity, occurred during the first week, and with a median duration of 4-5 days.2 Overall, 7.1% of patients discontinued participation in the clinical trial compared to 3.2% for placebo.1 In those with adverse effects, 8.8% randomized to vilazodone had adverse effects considered to be severe compared to 5.4% for placebo.3 Sexual dysfunction was assessed with the Arizona Sexual Experience Scale (ASEX). Sexual dysfunction was not associated with vilazodone treatment in this study.2 Overall, in placebo-controlled studies, the frequencies of decreased libido ranged from 2% to 5% in males and 3% or less for females compared to 0% to 1% for placebo.1 Less frequent events included abnormal orgasm, and delayed ejaculation and erectile dysfunction in males. As with other serotonergic antidepressants, there is a box warning for suicidal thinking and precaution regarding abrupt discontinuation of the drug.
Clinical Implications
Vilazodone is the newest serotonergic antidepressant to enter a crowded market, but is the only one that acts as a serotonin reuptake inhibitor and partial agonist for 5-HT1A receptor. 5-HT1A receptor agonists, such as buspirone, have been used to augment the effect of antidepressants particularly in patients with anxiety.4,5 Its low incidence of sexual dysfunction is encouraging. However, it is not known whether vilazodone offers any clinical advantage over other antidepressants since direct comparative studies have not been published. Until this has been established, vilazodone is another antidepressant with a "novel" dual mechanism of action.
References
1. Viibryd Prescribing Information. January 2011. Trovis Pharmaceuticals.
2. Rickels K, et al. Evidence for efficacy and tolerability of vilazodone in the treatment of major depressive disorder: A randomized, double-blind, placebo-controlled trial. J Clin Psychiatry 2009;70:326-333.
3. Khan A. Vilazodone, a novel dual-acting serotonergic antidepressant for managing major depression. Expert Opin Investig Drugs 2009;1:1753-1764.
4. Blier P, Ward NM. Is there a role for 5-HT1A agonists in the treatment of depression? Biol Psychiatry 2003;53:193-203.
5. Albert PR, Francois BL. Modifying 5-HT1A receptor gene expression as a new target for antidepressant therapy. Front Neurosci 2010;17:35.
A new antidepressant that combines selective serotonin reuptake inhibition with partial agonism of the 5-HT1A receptor has been approved by the FDA. Vilazodone is marketed by Trovis Pharmaceuticals as Viibryd(TM).Subscribe Now for Access
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