Does adding noradrenaline reuptake inhibition to selective serotonin reuptake inhibition improve efficacy in patients with depression? A systematic review of meta-analyses and large randomised pragmatic trials

Selective serotonin reuptake inhibitors (SSRIs) are recommended as first-line pharmacological treatment for depression and are the most commonly prescribed class of antidepressants. However, there is substantial evidence that noradrenaline has a role in the pathogenesis and treatment of depression. This review aims to examine the evidence of including noradrenaline reuptake inhibition with serotonin reuptake inhibition with respect to increasing efficacy in the treatment of depression. Evidence from meta-analysis of randomised controlled trials (RCTs) and randomised pragmatic trials was found in support of greater efficacy of the serotonin noradrenaline reuptake inhibitors (SNRIs), venlafaxine and duloxetine, in moderate to severe depression compared to SSRIs but no evidence was found for superiority of milnacipran. There is sufficient current evidence that demonstrates an increase in efficacy, when noradrenaline reuptake is added to serotonin (5-HT) reuptake, to suggest that patients with severe depression or those who have failed to reach remission with a SSRI may benefit from treatment with a SNRI. However, as these conclusions are drawn from the evidence derived from meta-analyses and pragmatic trials, large adequately powered RCTs using optimal dosing regimens and clinically relevant outcome measures in severe depression and SSRI treatment failures are still required to confirm these findings.