Effect of fluvoxamine on plasma risperidone concentrations in patients with schizophrenia.

摘要: The effect of fluvoxamine on plasma concentrations risperidone and its active metabolite 9-hydroxyrisperidone (9-OH-risperidone) was investigated in 11 schizophrenic patients with prevailingly negative or depressive symptoms. Additional fluvoxamine, at the dose 100 mg/day, administered for 4 weeks to stabilized (3-6 mg/day). Mean risperidone, 9-OH-risperidone moiety (sum 9-OH-risperidone) were not significantly modified following co-administration fluvoxamine. After weeks, dosage increased 200 mg/day five then maintained until end week 8. At final evaluation, mean levels six who still receiving initial dose, while slightly but (by a 26% over pretreatment; P < 0.05) subgroup subjects treated mg/day. Fluvoxamine well tolerated no patient developed extrapyramidal side effects. These findings indicate that dosages up is associated clinically significant changes concentrations. However, higher doses may elevate levels, presumably as result dose-dependent inhibitory CYP2D6-and/or CYP3A4-mediated 9-hydroxylation risperidone.