RESUMEN
BACKGROUND: Antipsychotic drugs are associated with serious side effects in children and adolescents including weight gain. It is still unknown whether therapeutic drug monitoring (TDM) can improve patient outcomes. AIM: To test whether the dried blood spot method is a valid and feasible method to measure antipsychotic drug concentrations with a fingerprick; to assess the relationship between antipsychotic drug concentrations, side-effects and effectiveness in minors. METHOD: A dried blood spot (DBS) method was developed and tested for validity and feasibility. 89 children and adolescents with autism spectrum disorder (ASD) and behavioral problems were included in the multicenter, prospective, observational study SPACe (NTR6050). Antipsychotic drug concentrations, side-effects and effectiveness were measured during a 6-month follow-up. RESULTS: The DBS method showed a higher variability than venipuncture in measuring antipsychotic drug concentrations, but seemed feasible in minors with behavioral problems. Higher risperidon trough concentrations were associated with more weight gain and more effectiveness. A therapeutic window with optimal effectiveness and minimal side-effects was defined. CONCLUSION: The DBS method can be used to measure antipsychotic drug concentrations in children and adolescents with ASD and behavioral problems. As a relationship between antipsychotic drug concentrations and clinical outcomes was established, TDM might improve safety and effectiveness of antipsychotic drugs in this population.