Safety and usage of atypical antipsychotic medicines in children: a nationwide prospective cohort study

Abstract

Objective: To study the safety and usage of atypical antipsychotic medicines in post-marketing use in a nationwide paediatric population.

Design: Prospective observational cohort study using prescription event monitoring and record linkage.

Population: New Zealand children aged < or =15 years, who were prescribed atypical antipsychotic medicines between April and July 2003.

Outcomes: Usage measures included prescription data for each medication, the diagnosis for which the patient was being treated and main target symptom. Safety outcome measures were all new clinical adverse events between the start of treatment (which could be before April 2003) and 30 November 2004.

Results: The cohort included 420 children aged 2-15 years. Total exposure to atypical antipsychotic medicines was 641.2 patient-years of treatment with most (94%) of the exposure being to risperidone. The most common diagnoses were disruptive disorders. The symptoms most frequently targeted by the atypical antipsychotic were aggression and difficult behaviour. The treatment of sleep disorders as a target symptom was reported in 3% of children. A total of 131 (31%) children experienced an adverse event. The most frequent adverse events reported were weight gain, severe dental caries and somnolence. The incidence of diabetes mellitus was 4 (95% CI 0.5, 15) cases per 1000 patient-years of treatment in this study. Four children prescribed risperidone developed symptoms of depression, giving an incidence of 8 (95% CI 2.0, 21) cases per 1000 patient-years of treatment.

Conclusions: This study provides a picture of 'real-life' use of atypical antipsychotics in a nationwide cohort of children. Most prescriptions were for risperidone and the most common diagnoses were disruptive disorders. Investigation of the symptoms targeted by these medicines identified unexpected use for the treatment of sleep disorders. Regarding safety, symptoms of depression were identified as a potential new signal for risperidone in the paediatric population. Further research is now required to investigate this.