Efficacy and tolerability of escitalopram versus citalopram in major depressive disorder: a 6-week, multicenter, prospective, randomized, double-blind, active-controlled study in adult outpatients.

BACKGROUND

The S-enantiomer of citalopram (escitalopram) is the active moiety linked to the anti-depressant effects associated with citalopram (the racemate). For escitalopram to be approved for the treatment of depression in Europe, findings from clinical trials of escitalopram are required to match previous results from studies of the racemate, citalopram.

OBJECTIVE

The aim of this study was to compare the efficacy and tolerability of escitalopram and citalopram in outpatients with major depressive disorder (MDD).

METHODS

This prospective, randomized, double-blind, active-controlled study was conducted at 8 psychiatric outpatient clinics in the Federation of Russia. Adult outpatients aged 25 to 45 years with MDD and a total score > or =25 on the Montgomery-Asberg Depression Rating Scale (MADRS) were eligible. Patients were randomly assigned to receive 6 weeks of treatment with fixed daily doses of escitalopram 10 mg, citalopram 10 mg, or citalopram 20 mg. Efficacy assessments were made at weeks 0 (baseline), 1, 4, and 6 (study end or last observation carried forward). The primary efficacy parameter was the change from baseline in MADRS total score. Secondary measures were the change from baseline in MADRS total score in a subgroup of severely depressed patients (baseline MADRS total score, > or =35), MADRS core depression subscale score, and Clinical Global Impression-Severity and Improvement (CGI-S and CGI-I) scores; and the proportions of patients classified as responders and remitters at study end. Tolerability was assessed using adverse events (AEs) recorded by the investigator.

RESULTS

Of 330 assessable randomized patients, 8 withdrew, including 7 who withdrew consent and 1 who withdrew due to recurrence of a preexisting event. Thus, 322 patients were included in the assessment (mean age, 35 years; 41.6% male; all white; escitalopram 10 mg, 108 patients; citalopram 10 mg, 106; citalopram 20 mg, 108). At study end, the mean (SE) change from baseline in MADRS total score was significantly greater in the escitalopram arm than in the 10- and 20-rag citalopram arms (-28.70 [0.78] vs -20.11 [0.80] and -25.19 [0.78]; both, P < 0.001). Improvements were more marked in the severely depressed subgroup (-30.33 [0.95] vs -20.87 [0.99] and -26.34 [0.91]). Changes in the CGI-S and CGI-I scores and the rates of response and remission were significantly greater in the escitalopram group compared with those in the citalopram 10- and 20-mg groups (CGI-S: -2.60 [0.10] vs -1.61 [0.10] and -2.05 [0.10]; CGI-I: +1.58 [0.09] vs +2.35 [0.10] and +1.80 [0.09]; response: 95.4% vs 44.3% and 83.3%; remission: 89.8% vs 25.5% and 50.9% [all, P < 0.001]). Mean (SE) changes from baseline in core depression subscale score were -19.00 (0.59), -13.00 (0.60), and -16.52 (0.58) with escitalopram, citalopram 10 mg, and citalopram 20 mg, respectively. The prevalence of AEs was significantly lower in the escitalopram group (7) compared with the citalopram groups (16 and 19 in the 10- and 20-mg groups, respectively; both, P < 0.05). Nausea (2 [1.9%], 5 [4.7%], and 7 [6.5%] patients in the escitalopram and citalopram 10- and 20-mg groups, respectively) and headache (1 [0.9%], 2 [1.9%], and 4 [3.7%]) were the most frequently reported AEs.

CONCLUSIONS

The results from this study suggest that escitalopram 10 mg was more effective than citalopram 10 and 20 mg at 6 weeks in these adult outpatients with MDD. All treatments were well tolerated.