Do equivalent doses of escitalopram and citalopram have similar efficacy? A pooled analysis of two positive placebo-controlled studies in major depressive disorder

Abstract

Escitalopram is the S-enantiomer of citalopram. In this study, we compared the efficacy of equivalent dosages of escitalopram and citalopram in the treatment of moderate to severe major depressive disorder (MDD), based on data from two, pooled, randomized, double-blind, placebo-controlled studies of escitalopram in which citalopram was the active reference. The primary efficacy parameter was the mean change from baseline in the Montgomery Asberg Depression Rating Scale (MADRS) total score. Significant differences in favour of escitalopram were observed for the MADRS [P<0.05, observed cases (OC)/last observation carried forward (LOCF)] and Clinical Global Improvement-Severity of Illness scores (CGI-S; P<0.05, OC/LOCF). Escitalopram separated from placebo at week 1 on the primary efficacy parameter, whereas citalopram first separated from placebo at week 6. An analysis of time to response showed that escitalopram-treated patients responded significantly faster to treatment than citalopram-treated patients (P<0.01). More patients responded to and achieved remission with escitalopram than to citalopram (P<0.05, OC). The HAMD scale was only used in the fixed-dose study, where escitalopram-treated patients had a significant reduction in HAMD-17 total score at week 8 compared to citalopram-treated patients (P<0.05, OC/LOCF). In the pooled subpopulation of severely ill patients (MADRS> or = 30), escitalopram-treated patients showed greater improvement than citalopram-treated patients (P<0.05, LOCF/OC). Escitalopram showed consistently superior efficacy compared to citalopram in the treatment of moderate to severe MDD on all efficacy parameters, and was similarly well tolerated.