Oxcarbazepine (OXC), a 10-keto analogue of carbamazepine, is an antiepileptic drug licensed for the treatment of partial seizures in children and adults, as monotherapy or adjunctive therapy [1]. In humans, OXC is rapidly metabolized in liver to 10-monohydroxy-carbazepine (MHD), its active metabolite. MHD blocks voltage-sensitive sodium channels, stabilizing hyperexcited neuronal membranes, thereby inhibiting repetitive firing and decreasing the propagation of synaptic impulses [2]. Recently, successful use of OXC in the management of disruptive behaviours in autistic patients has also been reported [3].Despite the fact that experience with OXC in the paediatric age is still limited, several observational studies indicate that the drug has a good long-term tolerability profile [4,5]. In clinical practice, the most commonly observed adverse events are rash, fatigue, nausea and somnolence [4]. Only four cases of OXC acute overdose have been reported to date [6][7][8][9], none of them in a paediatric patient. We describe the case of a 13-year-old boy who presented with somnolence after the ingestion of 15 g of OXC, and provide concomitant serum concentrations of both OXC and MHD.A 13-year-old boy (weight 60 kg, height 175 cm) was brought to the Emergency Department by his mother because of accidental ingestion of 250 ml of Trileptal™ suspension (OXC solution, 60 mg l -1 ; Novartis, Barcelona, Spain) 1 h before; he had vomited shortly after the intake. No other drugs had been ingested. The patient had been diagnosed with autism spectrum disorder at the age of 4 years and was receiving risperidone (1 mg three times a day; Risperdal Flas™, Janssen-Cilag, Madrid, Spain) from the age of 10 years, together with behaviour modification. Treatment with OXC (300 mg twice daily) had been implemented 6 months earlier to treat persistent aggression towards others and head banging, with good tolerance to treatment and improvement in his disruptive behaviour.On admission, the patient's vital signs were as follows: blood pressure 105/47; pulse 75 beats min -1 ; respiratory rate 15 breaths min -1 ; haemoglobin saturation while breathing room air, 99%; temperature 36.9°C. He was somnolent (minimal Glasgow Coma Scale 13) but arousable to pain stimuli. Normal tendon and pupillary reflexes were present. Nystagmus and tremor were not observed; gait disturbances were not evaluable. The rest of the physical examination was unremarkable. The ECG was within normal limits (sinus rhythm, QRS 85 ms, and QTc 410 ms), and laboratory testing showed normal values for complete blood count, blood gases, protein and albumin levels, kidney and liver functions, and electrolyte concentrations.
