Myoclonus secondary to the concurrent use of trazodone and fluoxetine

A 39-y-o male with a history of human immunodeficiency virus infection and depression was admitted for diagnosis and treatment of tuberculosis and pneumocystis carinii pneumonia infections. Prior to admission, he was on 50 mg trazodone every evening for 2 mo for depression. He was admitted with a 2-w history of fever chills and fatigue and on admission had hand tremors which disappeared at rest. Four days post-admission the trazodone dose was increased to 100 mg and 20 mg fluoxetine was initiated. He became increasingly anxious and his hand tremor worsened 3 d after initiation of the regimen. To rule out drug induced tremor, both trazodone and fluoxetine were discontinued and symptoms resolved in 7 d. Clinicians should be aware of the potential for excessive seratonergic activities secondary to trazodone + fluoxetine interactions causing a worsening myoclonus adverse event.