The National Authority of Medicines and Health Products (INFARMED) issued a warning on Tuesday about the risk of accidental overdose in pediatric patients using this antipsychotic, which is prescribed for conditions including delusional psychoses like schizophrenia.
INFARMED noted that the overdoses were primarily due to misinterpretation of dosing measurements in the syringes/pipettes that accompany the medication. Symptoms reported included tremors, muscle rigidity, motor slowness, and difficulties in movement.
Healthcare professionals were urged to instruct caregivers and patients on the correct use of the dosing devices, emphasizing the importance of recognizing overdose symptoms and the need for immediate medical attention if an overdose is suspected or confirmed.
INFARMED, in response to inquiries, mentioned that the European Medicines Agency’s assessment concluded that the majority of overdose cases in children resulted from errors in reading decimal points in the administration devices.
The authorities have recommended that holders of marketing authorizations for medicines containing risperidone in oral solution form should revise the informational leaflet and dosing device if necessary to enhance visibility and clarity, including illustrations to aid patients and caregivers in accurately measuring dosages.
INFARMED stated that these changes are currently being implemented in Portugal, and upon completion, additional communication will be provided to all pharmacies to equip them with the best advice for patients and caregivers regarding the correct use of these medications and their administration devices.
According to the data provided by the regulator, there have been 298 cases of accidental overdose with risperidone 1 mg oral solution in children and adolescents (aged 3 to 15) between 2021 and the first half of 2025.
INFARMED recognized that other situations such as accidental ingestion might also be included in these cases, indicating that most were due to errors in using the administration device. Of these, 28 cases required specific treatment interventions.
