Duloxetine in the acute and long-term treatment of major depressive disorder: a placebo- and paroxetine-controlled trial.

BACKGROUND

Duloxetine is a balanced and potent dual reuptake inhibitor of serotonin (5-HT) and norepinephrine (NE) that has previously been shown to be effective in the acute treatment of major depressive disorder (MDD). This placebo-controlled study assesses the safety and efficacy of duloxetine (80 or 120 mg/day) and paroxetine (20 mg QD) during an initial 8-week acute phase and subsequent 6-month continuation phase treatment of MDD.

METHOD: In this randomized, double-blind, placebo-controlled trial, adult outpatients (age >or= 18 years) meeting DSM-IV criteria for MDD received placebo (n = 93), duloxetine 80 mg/day (40 mg BID; n = 95), duloxetine 120 mg/day (60 mg BID; n = 93), or paroxetine (20 mg QD; n = 86) for 8 weeks. Patients who had a >or= 30% reduction from baseline in HAMD(17) total score during the acute phase were allowed to continue on the same (blinded) treatment for a 6-month continuation phase. Efficacy measures included the 17-item Hamilton Rating Scale for Depression (HAMD(17)) total score, HAMD(17) subscales, the Montgomery-Asberg Depression Rating Scale (MADRS), the Hamilton Anxiety Rating Scale (HAMA), Visual Analog Scales (VAS) for pain, the Clinical Global Impression of Severity (CGI-S) and Patient Global Impression of Improvement (PGI-I) scales, the 28-item Somatic Symptom Inventory (SSI), and the Sheehan Disability Scale (SDS). Safety and tolerability were assessed using treatment-emergent adverse events, discontinuations due to adverse events, vital signs, ECGs, laboratory tests, and the Arizona Sexual Experiences Scale (ASEX).

RESULTS

During the acute phase, patients receiving duloxetine 80 mg/day, duloxetine 120 mg/day, or paroxetine 20 mg QD had significantly greater reductions in HAMD(17) total score compared with placebo. Both duloxetine (80 and 120 mg/day) and paroxetine treatment groups had significantly greater improvement, compared with placebo, in MADRS, HAMA, CGI-S, and PGI-I scales. Estimated probabilities of remission at week 8 for patients receiving duloxetine 80 mg/day (51%), duloxetine 120 mg/day (58%), and paroxetine (47%) were significantly greater compared with those receiving placebo (30%). The rate of discontinuation due to adverse events among duloxetine-treated patients (80 and 120 mg/day) did not differ significantly from the rate in the placebo group. Treatment-emergent adverse events reported significantly more frequently by duloxetine-treated patients than by patients receiving placebo were constipation (80 and 120 mg/day), increased sweating (120 mg/day), and somnolence (120 mg/day). The incidence of acute treatment-emergent sexual dysfunction in duloxetine- and paroxetine-treated patients was 46.5% and 62.8%, respectively. During the 6-month continuation phase, duloxetine (80 and 120 mg/day) and paroxetine treatment groups demonstrated significant improvement in HAMD(17) total score. Treatment-emergent adverse events occurring most frequently in each active treatment group during the continuation phase were viral infection (duloxetine 80 mg/day), diarrhea (duloxetine 120 mg/day), and headache (paroxetine 20 mg QD).

CONCLUSION

These data support previous findings that duloxetine is safe, efficacious, and well tolerated in the acute treatment of MDD. Furthermore, these data provide the first demonstration under double-blind, placebo-controlled conditions that the efficacy and tolerability of duloxetine are maintained during chronic treatment.