Plasma Concentrations of Risperidone and 9-Hydroxyrisperidone During Combined Treatment With Paroxetine

Abstract
The effects of paroxetine on steady-state plasma concentrations of risperidone and its active metabolite 9-hydroxyrisperidone (9-OH-risperidone) were studied in 10 patients with schizophrenia or schizoaffective disorder. Patients stabilized using risperidone therapy (4–8 mg/d) also received paroxetine (20 mg/d) for 4 weeks. During paroxetine administration, mean plasma concentrations of risperidone increased significantly (P