An analysis of the data which are available, published in the European Journal Psychotherapy and Psychosomatics, discloses that the maker's claims are not warranted.
Duloxetine inhibits both serotonin and norepinephrine reuptake and is marketed as a treatment for both the core emotional symptoms and painful physical complaints that often accompany depression. Some studies have found that duloxetine is efficacious in treating painful symptoms associated with depression but these findings have been inconsistent. Several narrative review articles have reached positive conclusions about the efficacy of duloxetine as an analgesic in depression but there has been no quantitative systematic review regarding the impact of duloxetine on pain among this population.
A meta-analysis of data pertaining to duloxetine's purported analgesic effects on depressed patients was thus undertaken. Studies were selected through searching Medline and Cochrane Trial databases as well as examining Lilly's public clinical trial database. A random effects model was used. Across five trials, the results indicate a very small (d = 0.115) and statistically nonsignificant (p = 0.057) analgesic effect for duloxetine.
Additionally, some of the relevant data on duloxetine's effects have not been reported fully, making it likely that the obtained results reflect an overestimate of its true impact on painful physical symptoms in depression. The current analysis is based on a small number of studies; further trials may yield significant results favoring duloxetine. Based upon the currently available evidence, the marketing of duloxetine as an antidepressant with analgesic properties for people with depression does not appear to be adequately supported.