Are All Antidepressants Really the Same? The Case of Fluoxetine: A Systematic Review

Objective: To systematically review the efficacy and tolerability of fluoxetine, the most widely studied of newer antidepressants, in comparison with all other antidepressants in the acute treatment of depression in patients aged more than 18 years.

Data Sources: Studies were identified through electronic searches of the Cochrane Collaboration Depression, Anxiety and Neurosis Controlled Trials Register and the Cochrane Central Register of Controlled Trials up to March 2004. The terms FLUOXETIN* OR adofen or docutrix or erocap or fluctin or fluctine or fluoxeren or fontex or ladose or lorien or lovan or mutan or prozac or prozyn or reneuron or sanzur or saurat or zactin were used. MEDLINE (1966-2004) and EMBASE (1974-2004) were searched using fluoxetine and randomized controlled trial or random allocation or double-blind method. No language restrictions were applied. Reference lists of relevant papers and previous systematic reviews were hand-searched for published reports up to March 2004.

Study Selection: Only randomized controlled trials (either blind or nonblind) were included.

Data Synthesis: 131 randomized controlled trials were eligible. A p value less than .01 was chosen to test the null hypothesis, and a 99% confidence interval was calculated to detect statistically significant differences with a high degree of confidence. Fixed- and random-effects relative risks, odds ratios (ORs), and Peto ORs were routinely calculated for each outcome measure. In terms of efficacy, we found a statistically significant difference favoring sertraline and venlafaxine over fluoxetine. In terms of tolerability, patients allocated to fluoxetine were less likely to leave the study early only in comparison with those allocated to amitriptyline and pramipexole.

Conclusions: This systematic review highlighted that there are differences between fluoxetine and specific comparator antidepressants. Several of the differences met a prespecified criterion for clinical significance. The statistical approach adopted in this systematic review could represent a useful tool for putting clinical trial data into practice.