Background: We compared the efficacy and tolerability of venlafaxine XR with that of fluoxetine in a multicenter, randomized, double-blind, placebo-controlled study in depressed outpatients.
Methods: Outpatients, 18 years and older, who met DSM-IV criteria for major depressive disorder were included (n = 301 randomized; 232 completed). Patients were randomly assigned to eight weeks of treatment with either venlafaxine XR 75-225 mg/day (n = 100), fluoxetine 20-60 mg/day (n = 103), or placebo (n = 98). The primary efficacy outcome measures were the final ratings on the Hamilton Rating Scale for Depression (HAM-D21) total score, HAM-D21 depressed mood item, Montgomery-Asberg Depression Rating Scale total score, and Clinical Global Impressions Scale.
Results: Withdrawal from the study due to adverse events occurred in 6% of the patients in the venlafaxine XR group and 9% of the patients in the fluoxetine group. Patients treated with venlafaxine XR, but only rarely those treated with fluoxetine, had statistically significant improvements in their depression ratings compared with placebo at the end of the study. The percentages of patients who achieved full remission of their depression (HAM-D21 total score < or = 7) at the end of treatment were 37%, 22% and 18% for the venlafaxine XR, fluoxetine and placebo groups, respectively. The differences in remission rates between venlafaxine XR and the other groups were statistically significant (p < 0.05).
Limitations: The superior remission outcome observed with venlafaxine XR treatment needs to be replicated in additional studies.
Conclusion: Venlafaxine XR is a well-tolerated and efficacious treatment for depression. The results of this study suggest that venlafaxine XR is as well-tolerated as fluoxetine but may have some efficacy advantages over fluoxetine.