Serum concentrations, therapeutic response and side effects in children and adolescents with impulsive-aggressive symptoms during risperidone therapy.

INTRODUCTION

The aim of this prospective naturalistic study was to examine for the first time the relationship between dosage, serum concentration and clinical outcome in children and adolescents with impulsive-aggressive symptoms during risperidone therapy.

METHODS

Steady state trough serum concentrations of risperidone and 9-hydroxyrisperidone (the active moiety) were measured in 103 subjects. The therapeutic effect was assessed by the clinical global impression improvement subscale and side effects by the Udvalg for Kliniske Undersogelser-side effect rating scale.

RESULTS

We found a linear relationship between the risperidone dose and the serum concentration of the active moiety (Spearman rho=0.53) and no correlation between the serum concentration and either the therapeutic effect or side effects. There was no effect of gender and co-medication.

DISCUSSION

This study has the typical limitations of naturalistic studies, therefore our results should be interpreted with caution. Based on the serum concentrations at the therapeutically effective dose range (0.25-1.5 mg/day) we obtained first information on a possibly appropriate therapeutic serum range for the risperidone treatment of children and adolescents with impulsive-aggressive symptoms. Further studies with greater sample sizes are needed to validate our results and to examine the influence of genetic polymorphisms on the serum concentration of risperidone.