As many as 50% of children with an autism spectrum disorder suffer from temper tantrums, aggression and self-harm as well. Pharmacological interventions are an important part of the multimodal treatment of these comorbid behavioural problems. Guidelines recommend antipsychotics as agents of first choice. In the Netherlands, almost 1 out of every 100 children use antipsychotics. During treatment with antipsychotics, metabolic side-effects are of great concern though. Even in short term studies in children show significant weight gain, and large epidemiological studies have shown an increased risk of type 2 diabetes.
In the ZonMW GGG funded (2015) SPACe study we researched the relationship between drug plasma levels and metabolic side effects in children. We developed a minimally invasive dry blood spot technique using finger pricks to determine plasma levels. In 30 children who used risperidone we developed a population pharmacokinetic model. We used this model to show a clear relationship of risperidone trough concentrations with weight gain over a 6 month period. Risperidone trough concentrations also predicted level of sedation, prolactin levels and effectiveness. These results indicate a therapeutic window exists. In SPACe 2 STAR we aim to reach further, by means of a randomised controlled trial we will test whether application of dosing advice based on risperidone trough concentrations is indeed able to reduce the number/severity of metabolic side effects in children.