Plasma Risperidone-related Measures in Children and Adolescents with Oppositional Defiant/Conduct Disorders

Area of Science:

• Pharmacology
• Pediatric Psychiatry
• Clinical Pharmacy

Background:

• Therapeutic drug monitoring (TDM) is crucial for optimizing medication efficacy and safety.
• Risperidone is frequently prescribed for disruptive behavior disorders in children and adolescents.
• Understanding pharmacokinetic variability in pediatric populations is essential for effective treatment.

Purpose of the Study:

• To investigate the time-dependent patterns of risperidone and its active metabolite, 9-hydroxyrisperidone.
• To analyze the influence of demographic factors on risperidone pharmacokinetics in pediatric patients.
• To inform TDM strategies for risperidone in youth with oppositional defiant and/or conduct disorder.

Main Methods:

• Plasma concentrations of risperidone and 9-hydroxyrisperidone were measured in 140 pediatric patients.
• Analysis included the active moiety (AM), ratio, and dose-corrected concentrations (C/D).
• Statistical comparisons were made based on sex, age (<16 vs. ≥16 years), body weight, and BMI, using t-tests and mixed-effects logistic regression.

Main Results:

• Females exhibited higher 9-hydroxyrisperidone and AM levels than males.
• Younger patients (<16 years) and lower-weight patients showed distinct concentration-to-dose ratios.
• Risperidone daily dose was the primary predictor for the risperidone/9-hydroxyrisperidone ratio, while dose, sex, and age predicted AM.

Conclusions:

• Clinicians should consider patient sex, age, and weight when adjusting risperidone doses.
• Body Mass Index (BMI) was not found to be a significant factor in dose adjustment.
• These findings support individualized TDM for risperidone in pediatric populations.