A double-blind comparison of paroxetine with imipramine in the long-term treatment of depression

The chronic and recurrent nature of major depression is well recognized, and recent data suggest that maintenance therapy with full-dose pharmacotherapy (i.e., the dose used to treat the index episode) is effective in preventing relapse and recurrence. We present results from a 1-year, double-blind trial of paroxetine and imipramine in patients who successfully completed a 6-week acute course of therapy. A total of 717 outpatients were included in the 6-week, randomized, double-blind, placebo-controlled comparative study of paroxetine and imipramine conducted at six centers. At the end of the acute treatment phase, patients showing a therapeutic response were eligible to enter a long-term extension of the study in which they would continue to receive the same drug (or placebo) in double-blind fashion for up to 1 year. Of the 219 patients who entered the long-term phase, 94 received paroxetine, 79 received imipramine, and 46 received placebo. During the 1-year maintenance study, both paroxetine and imipramine were more effective than placebo in maintaining euthymia among patients who had responded to short-term treatment. However, approximately twice as many imipramine-treated patients dropped out of the study prematurely because of adverse experiences compared to paroxetine-treated patients, suggesting that paroxetine is more readily tolerated than imipramine during long-term treatment.