Fluoxetine augmentation in bipolar disorder patients on maintenance lithium treatment

Lithium augmentation during long-term treatment with antidepressants has long been considered an effective therapeutic strategy in the treatment of depressive syndromes. This paper deals with an 'opposite' strategy, i.e. the use of serotonin reuptake inhibitors (SRIs) during maintenance lithium treatment in bipolar disorder (BP) patients who may present a breakthrough depressive syndrome. The study involved 26 patients on maintenance lithium treatment for a mean of 38 months (mean serum lithium level=0.57 mEq/l). Mean fluoxetine dose was 29.3 mg/day for a mean period of 7.36 weeks. Median HDRS scores before and after fluoxetine augmentation were 14 and 6, respectively. The results provide evidence for the efficacy of fluoxetine augmentation in the treatment of breakthrough depressions occurring in bipolar disorder patients during maintenance lithium treatment. The neuropharmacological explanation of the augmentation is not yet well understood, but it is conceivable that the improvement of the depressive symptoms may be related to the increase in serotonergic function provided by combination of the two treatments.