Possible serotonin syndrome associated with buspirone added to fluoxetine

Objective:To report the development of a possible serotonin syndrome in a patient taking buspirone and fluoxetine.Case summary:A 37-year-old white man taking fluoxetine 20 mg/d for generalized anxiety disorder developed confusion, diaphoresis, incoordination, diarrhea, and myoclonus after buspirone was added to the drug regimen.Discussion:Serotonin syndrome is a potentially lethal condition of serotonin hyperstimulation, which may develop rapidly or over the course of several weeks. Symptoms of serotonin syndrome typically occur following additions or increases of serotonin-enhancing drugs. Although buspirone has variable effects on post- and presynaptic 5-HT1A receptors that may reduce the risk of serotonin syndrome when administered as a single agent, it may cause an adverse reaction when given with other serotonergic drugs.Conclusions:Symptoms consistent with serotonin syndrome may develop with the concurrent administration of buspirone and fluoxetine.