Manic Switching in Patients Receiving Duloxetine

A 58-year-old man with a 2-month major depressive episode was seen in our outpatient clinic. There were no psychiatric antecedents, and both the patient and his family denied any episodes suggesting mania or hypomania. The patient did not have a family history of bipolar disorder, and his medical history was unremarkable.

Treatment with paroxetine (40 mg daily) resulted in initial partial remission, followed by severe relapse. Duloxetine (60 mg daily) was substituted and rapid recovery was obtained. Four months later—while still on duloxetine—admission was necessary because the patient experienced a manic syndrome with psychotic features. General examination and routine studies (rapid plasma reagin, human immunodeficiency virus, thyroid function, blood chemistry, and computed tomography scan) showed results within normal limits.

The second patient was a 40-year-old woman who had previously showed symptoms of bulimia and alcohol abuse. She also had interspersed periods of increased activity with times of more inhibition, for which medical care was never required. Several months before, she suffered a transient, acute psychotic episode that required hospital admission and short treatment with an atypical antipsychotic. Her status at the time included anhedonia, hypersomnia, anergy, difficulty in concentrating, and a sense of worthlessness. Six weeks after beginning treatment with duloxetine, the patient’s mood improved. Nevertheless, after 3 months of treatment (120 mg daily), a sudden manic episode with psychotic symptoms was diagnosed, and inpatient management was required.