Efficacy and Tolerability of Mirtazapine Versus Paroxetine in the Treatment of Major Depressive Disorder

Objective: To compare the efficacy and tolerability of paroxetine and mirtazapine in the treatment of major depression. Data sources: Searches were conducted to identify studies through Medline (1980–2011), PsycInfo (1980–2011) and PubMed databases up to June 2011. The searches were not restricted to publication type or clinical trial design. Study selection: A clinical trial was included if it described a trial of paroxetine versus mirtazapine in patients with major depression, based on the research evidence of reviews. Data abstraction: Three assessors analyzed the quality of the trials and extracted study design data, trial features, efficacy and tolerability assessment tools, discontinuation reasons for both antidepressants and remitter and responder rates. Results: We included six randomized controlled trials, one open-label, randomized controlled trial and four systematic reviews and meta-analysis. Rates of remission and response between mirtazapine and paroxetine were compared: at the beginning (1–2 weeks) there were statistically significant differences in mirtazapine treated patients, but these were not found at the end of assessment period (6–8 weeks). Discontinuation rates between the two drugs showed no differences, with an adverse event profile characteristic of each drug. Conclusions: Mirtazapine and paroxetine were equally effective and well-tolerated in major depressive disorder. Differences in effectiveness were only observed in the first or second week of treatment when mirtazapine showed earlier onset of action.