Efficacy and tolerability of vilazodone for the acute treatment of generalized anxiety disorder: A meta-analysis

Abstract

Purpose: A systematic review and meta-analysis of all relevant randomized controlled trials was conducted to evaluate the safety and efficacy of vilazodone in the acute treatment of generalized anxiety disorder (GAD).

Methods: The literature was searched through all relevant databases in order to identify clinical trials on the use of vilazodone in the treatment of GAD. Once the trials were identified, data was extracted and analyzed using Revman5.3 and open meta-analyst. Assessment of continuous outcomes relied upon standardized mean difference, while binary outcomes were evaluated via relative risk, absolute risk reduction and NNT/NNH.

Results: A total of 3 well-designed randomized controlled trials with a duration of 10 weeks were conducted, with a total of 844 (intent to treat population) randomized to vilazodone (20-40mg, mean dose=31.42mg) and 618 to placebo. The study drug was significantly superior (p<0.001) to placebo in continuous primary outcome measures (HAMA reduction at week 8, CGI-S reduction at week 8 and CGI-I score at week 8). Binary outcome measures however are not as promising, probably reflecting a small effect size [NNT=10 (6.67, 21.28) for induction of response according to the HAMA scale and NNT=12 (7.58, 34.48) for the CGI-I scale], although statistical significance (p<0.01) was attained for both. The study drug was significantly (p<0.001) more likely than placebo to induce adverse effects and to be discontinued due to adverse effects NNH=14 (10.31, 22.22), most common of which were nausea and diarrhea.

Discussion: Vilazodone was superior to placebo in the short term treatment of GAD. However, due to the small effect size and high incidence of adverse events, the utility of vilazodone in the treatment of GAD remains unclear. Likelihood to be helped (HAMA response) or harmed (discontinuation due to adverse events) was inconclusive [1.4 (0.48, 3.33)], demonstrating a need for further trials and direct comparisons of vilazodone to the standard treatments for the disorder. Thus vilazodone cannot be recommended yet as a first line agent.

Conclusion and limitations: Vilazodone is an effective treatment for generalized anxiety disorder, though further trials are required for a more adequate comparison with established treatments, as well as long term maintenance studies to determine the validity of claims regarding the absence of sexual side effects.

Keywords: Antidepressants; Generalized anxiety disorder; Meta-analysis; Vilazodone.