Effectiveness and Safety of the Combination of Fluoxetine and Olanzapine in Outpatients With Bipolar Depression

We studied the effectiveness of olanzapine/fluoxetine combination (OFC) treatment of bipolar depressive episode (7 weeks, study period 1 [SP1]). Study period 1 responders (mean modal daily OFC dosage, 10.8/27.8 mg) were randomized to OFC continuation treatment or olanzapine (OLZ) monotherapy starting at 10 mg (12 weeks, SP2). Seventy-three percent of the 114 patients who entered into SP2 completed the trial. The Montgomery-Asberg Depression Rating Scale total score changes from baseline in SP1 (primary outcome) were significant (-20 +/- 10, P < 0.001) and, during SP2, worsened for patients in the OLZ group (OFC vs OLZ, -0.4 +/- 7.55 vs +8.2 +/- 14.1, respectively; P < 0.001). During SP1, 69% responded and 59% remitted. During SP2, significantly more patients in the OFC group maintained response (31.3% vs 12.5%) and remission (71.4% vs 39.6%) than patients in the OLZ group. Treatment-emergent adverse events with OFC (SP1 and SP2) included increased appetite, increased weight, somnolence, anxiety, insomnia, and depressed mood. Since visit 1, the mean weight increases (in pounds) were 4.8 +/- 6.8 for SP1 (P < 0.001) and 6.3 +/- 10.3 (OFC) or 10.7 +/- 11.3 (OLZ) for SP2; 50% (OLZ) and 33% (OFC) of the patients had a 7% or higher weight increase. For cholesterol, triglycerides, and low-density lipoprotein levels and some hepatic enzymes, there were statistically and clinically significant changes in both study periods but no differences between the SP2 groups. Study limitations included the open-label design and exclusion of the SP1 nonresponders from SP2. These study results suggest that improvements resulting from 7 weeks of acute OFC treatment of a bipolar depressive episode are maintained in responders for an additional 12 weeks with OFC, but switching to OLZ alone may result in symptom worsening.