Efficacy and safety of morning versus evening fluoxetine administration.

A total of 120 patients who met DSM-III criteria for unipolar major depressive episode were equally randomized to fluoxetine a.m. or fluoxetine p.m. treatment groups, such that 30 patients were in each group at each of two sites. Patients received 20 to 80 mg of fluoxetine every day for 5 weeks; the dose was based on clinical response. Highly significant within-treatment improvement was reflected by changes in mean scores on the Hamilton Rating Scale for Depression (total score and factors), the Raskin Depression Scale, the Covi Anxiety Scale, the Clinical Global Impressions Scale for Severity, and the Clinical Global Impressions Scale for Improvement. No significant differences occurred between the a.m. and p.m. groups for any efficacy variable. Evaluation of adverse events and vital signs indicated no clinically significant differences between the two treatment groups. The data indicate that fluoxetine is equally efficacious and well tolerated regardless of the time of day it is administered and suggest that fluoxetine may be administered at either time of day without affecting clinical course.