A number of different antidepressant types are available, and many randomised trials (most modest in size and statistical power) have evaluated their relative effectiveness. Venlafaxine is a well established antidepressant, and previous work has indicated that it may be superior to SSRIs in treating depression.

We conducted a meta analysis of all available trials comparing venlafaxine and SSRIs examining the outcomes of response, remission and relative tolerability. Trials were identified through searches of Medline, Embase, Cochrane Library and through accessing unpublished trials held by the manufacturer. Results based on intention to treat analyses, were pooled using theoretically exact conditional maximum likelihood methods for fixed effects, and numerical simulation for full random effects.

We identified 34 trials comparing venlafaxine with an SSRI, including 6374 patients. Venlafaxine was compared with fluoxetine in 18 trials, with paroxetine in 6 trials and with sertraline in 4 trials. Other comparators were citalopram (2 trials), escilatopram (2 trials) and fluvoxamine (2 trials). Response to venlafaxine was superior to that of alternative SSRIs, odds ratio 1.17 (95% CI 1.05 to 1.30; P = 0.0052). Similarly, for remission, venlafaxine was superior to SSRIs, odds ratio 1.24 (95% CI 1.10 to 1.40; P = 0.0004). Similar results were identified for full random effects analyses. Overall drop out was similar for SSRIs and venalfaxine.

Venlafaxine is more effective then SSRIs in achieving response and remission, and appears similarly tolerated.