Clonidine overdose in childhood: implications of increased prescribing

To highlight the increase in the number of cases of clonidine overdose admitted to a specialist paediatric hospital, with particular reference to the clinical features, clinical course and circumstances surrounding the incident.

Cases of clonidine overdose were identified by review of the emergency department attendance register, the intensive care unit database and inpatient statistics collection. Case notes were reviewed to determine the clinical features, history and clinical course in each case.

Fifteen patients experienced 16 overdoses during the period 1990-97 inclusive. Only one case occurred before 1994. Depressed level of consciousness and bradycardia were the most common clinical manifestations, and were observed in 75 and 88% of cases respectively. There were no fatalities. Five patients received naloxone. Other treatment modalities included gastrointestinal decontamination, atropine, ventilation and inotropic support. Fourteen cases occurred in association with medication prescribed for attention-deficit hyperactivity disorder (ADHD).

Clonidine overdose is a potentially serious condition, often requiring intensive care management. Our experience suggests that it is a growing problem, related in part to its increased use in the treatment of ADHD. Preventive strategies, including raising the level of awareness of risks, changes to packaging and appropriate selection of patients for treatment, need consideration if further overdoses are to be prevented.