Relapse in patients on long-term fluoxetine treatment: response to increased fluoxetine dose

Although several studies have examined the long-term efficacy of antidepressants, relatively little attention has been paid to the management of relapses or recurrences during continued antidepressant treatment. This study examined whether depressed patients who had recovered and then relapsed on fluoxetine 20 mg/day would benefit from an increase in fluoxetine dose.

Eighteen patients who relapsed on fluoxetine 20 mg/day during long-term treatment with fluoxetine as part of a placebo-controlled study had their fluoxetine dose raised to 40 mg/day and were followed for at least 1 month (mean time = 4.7 months).

Twelve (67%) were full responders, 3 (17%) partial responders, and 3 (17%) dropped out because of side effects (e.g., insomnia and agitation). Of those patients who had either full or partial response (N = 15; 83%), 3 complete responders had a recurrence on 40 mg/day after a mean of 5.8 months and 1 partial responder had a recurrence 11 months later. Overall, 11 (61%) of 18 patients maintained their response during their follow-up while taking the higher dose of fluoxetine.

An increase in dose of fluoxetine to 40 mg/day appears to be an effective strategy in the treatment of relapse among depressed patients who had initially responded to fluoxetine 20 mg/day.