Short- and long-term effects on prolactin of risperidone and olanzapine treatments in children and adolescents.

This study investigated prolactin levels in two groups of children and adolescents receiving risperidone (N=29) or olanzapine (N=13). It focused not only on significant differences but also on effect sizes; took into account dose effects and gender differences; used a longitudinal design (months 1, 3, 6 and 12) that helped control for individual differences; and took into account response differences due to the duration of antipsychotic treatment. Additionally, this study investigated tolerance development using statistical tests, and explored the effect of antipsychotic plasma concentrations at months 1 and 3.

Effect of topiramate on plasma concentrations of clozapine, olanzapine, risperidone, and quetiapine in patients with psychotic disorders.

Objectives: To investigate the effect of topiramate on the steady-state plasma concentrations of the second-generation antipsychotics--clozapine, olanzapine, risperidone, and quetiapine--in patients with schizophrenia or bipolar disorder.

Methods: Thirty-eight outpatients on long-term treatment with clozapine (250-500 mg/d, n = 10), olanzapine (10-20 mg/d, n = 12), risperidone (3-6 mg/d, n = 9), or quetiapine (200-600 mg/d, n = 7) received adjunctive topiramate, gradually titrated up to a final dosage of 200 mg/d for 6 weeks. Pharmacokinetic assessments were made at baseline and at the end of treatment weeks 4 and 8 at topiramate dosages of 100 and 200 mg/d, respectively.

Effect of adjunctive lamotrigine treatment on the plasma concentrations of clozapine, risperidone and olanzapine in patients with schizophrenia or bipolar disorder.

The effect of lamotrigine on the steady-state plasma concentrations of the atypical antipsychotics clozapine, olanzapine, and risperidone was investigated in patients with schizophrenia or bipolar disorder stabilized on chronic treatment with clozapine (200-500 mg/day; n = 11), risperidone (3-6 mg/day; n = 10) or olanzapine (10-20 mg/day; n = 14)). Lamotrigine was titrated up to a final dosage of 200 mg/day over 8 weeks, and pharmacokinetic assessments were made at baseline and during treatment weeks 6 and 10, at lamotrigine dosages of 100 and 200 mg/day respectively. The plasma concentrations of clozapine, norclozapine, risperidone, and 9-hydroxy-risperidone did not change significantly during treatment with lamotrigine.

Determination of olanzapine in human plasma by reversed-phase high-performance liquid chromatography with ultraviolet detection.

A sensitive high-performance liquid chromatographic method with ultraviolet absorbance detection for the determination of olanzapine in human plasma is described. Clozapine was used as internal standard. Analytes were concentrated from alkaline plasma by liquid-liquid extraction with n-hexane-isoamyl alcohol (90:10, vol/vol).

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

The effect of fluvoxamine on plasma concentrations of 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 of 100 mg/day, was administered for 4 weeks to patients stabilized on risperidone (3-6 mg/day). Mean plasma concentrations of risperidone, 9-OH-risperidone and the active moiety (sum of the concentrations of risperidone and 9-OH-risperidone) were not significantly modified following co-administration with fluvoxamine.

Plasma concentrations of risperidone and olanzapine during coadministration with oxcarbazepine.

Purpose: Oxcarbazepine (OZC) is a second-generation antiepileptic drug (AED) that also may be used as a mood stabilizer. Unlike carbamazepine (CBZ), which is an inducer of the cytochrome P-450 isoforms and may accelerate the elimination of several therapeutic agents, OXC seems to have only a modest inducing action. The aim of this investigation was to evaluate the effect of a treatment with OXC on plasma concentrations of the new antipsychotics risperidone and olanzapine.

Plasma risperidone concentrations during combined treatment with sertraline.

The effect of sertraline on the steady-state plasma concentrations of risperidone and its active metabolite 9-hydroxyrisperidone (9-OH-risperidone) was studied in 11 patients with schizophrenia or schizoaffective disorder. To treat concomitant depressive symptoms, additional sertraline, at the dose of 50 mg/d, was administered for 4 weeks to patients stabilized on risperidone (4-6 mg/d). Mean plasma concentrations of risperidone, 9-OH-risperidone, and the active moiety (sum of the concentrations of risperidone and 9-OH-risperidone) did not change significantly during combined treatment with sertraline.