Efficacy and safety of mirtazapine in major depressive disorder patients after SSRI treatment failure: An open-label trial

Objective: To evaluate the efficacy and safety of mirtazapine in depressed outpatients who have shown nonresponse or intolerance to selective serotoni n reuptake inhibitor (SSRI) therapy. Method: In this open-label, 8-week; st udy, the efficacy and safety of mirtazapine among 103 outpatients with DSM- IV major depressive disorder who had failed previous therapy with an SSRI ( fluoxetine, paroxetine, or sertraline) were evaluated. The primary efficacy measure was the 17-item Hamilton Rating Scale for Depression (HAM-D-17), a nd safety assessments included reported adverse events, routine laboratory assessments, physical examinations, and assessments of vital signs. A 4-day washout period followed by mirtazapine treatment was compared with an imme diate switch from the SSRI to mirtazapine. Results: Based un mean HAM-D-17 scores at endpoint and response rates of 48% based on the criterion of grea ter than or equal to 50% reduction in HAM-D-17 score, mirtazapine was found to be an effective treatment fur a substantial proportion of patients for whom an SSRI was ineffective and/or poorly tolerated. Mirtazapine was well tolerated, with sedation and appetite increase/weight gain the most commonl y reported adverse events. In addition, no difference in efficacy, safety, or tolerability was observed fur patients undergoing an immediate switch fr om an SSRI (after having been tapered to the minimal effective dose) to mir tazapine, compared with those undergoing the imposition of a 4-day drug-fre e washout. Conclusion: These results suggest that an immediate switch to mi rtazapine may be a valid therapeutic option among patients who cannot toler ate or do not respond to SSRIs.