Poisonings with ADHD medication in children under the age of 5 years in Australia: a retrospective study, 2004–2019

OBJECTIVE: To describe the temporal relationships in attention-deficit hyperactivity disorder (ADHD) medication poisoning exposures in children; describe patient demographics, medications involved, poisoning exposure reasons and disposition. DESIGN: A population-based, retrospective cohort study of calls to Australia’s largest Poisons Information Centre. Poisoning exposure counts and dispensing-adjusted rates were modelled with Poisson, quasi-Poisson and negative binomial regression where appropriate. SETTING: Calls to the New South Wales Poisons Information Centre and dispensings on the Pharmaceutical Benefits Scheme. PATIENTS: Children under the age of 5 years. RESULTS: There were 1175 poisoning exposures to ADHD psychostimulants, 2004–2019; averaging 73 per year. Accidental poisonings accounted for 94% of cases. Methylphenidate was most frequently implicated (63%). Thirty-four per cent of cases were referred to hospital and a further 21% of calls were made by hospital staff. Poisoning exposure counts for all ADHD psychostimulants increased by 2.7% (95% CI=0.42% to 4.9%) per year; however, this differed by agent. Methylphenidate poisoning exposures increased by 5.2% per year (95% CI=4.3% to 6.1%), lisdexamfetamine increased by 62% per year (95% CI=48% to 76%), while dexamphetamine poisoning exposures decreased by 5.5% per year (95% CI=−9.5% to −1.4%). These trends are reflected in the number of dispensings; however, dispensings increased at a faster rate than exposures. When poisoning exposures were expressed as dispensing-adjusted rates, there was a 16% decrease (95% CI=−20% to −13%) per year. CONCLUSIONS: ADHD medication use has increased, associated with an increased number of paediatric poisoning exposures. However, poisoning exposures per dispensed prescription has decreased. The majority of cases required hospitalisation, indicating the need for further poisoning prevention strategies.