Reactions 1449 - 27 Apr 2013

O SCarbamazepine overdose

Intoxication, hypouricaemia, cyclic coma anddelirium in a child: case report

An 11-year-old boy developed carbamazepine intoxication,hypouricaemia, cyclic coma and delirium following anoverdose of carbamazepine.

The boy, who had idiopathic epilepsy, was receivingcarbamazepine 400mg twice daily (23 mg/kg/day) [route notstated]. One evening, he experienced dizziness and fell asleep[duration of treatment to reaction onset not stated]. When hedid not respond to attempts to wake him, he was taken to ahospital. Upon presentation, he was confused, aggressive andagitated.

The boy continued receiving his usual dose ofcarbamazepine. Within the next 24 hours, he developeddeterioration of his mental state with cyclic variations ofconsciousness. He also developed ataxia, generalised bodytremor and horizontal nystagmus. Examination revealedsevere hypotonia and hyporeflexia, while tests revealed anelevated blood carbamazepine concentration and a low serumurate level. A detailed history revealed that he had taken13 tablets (2.6g) of carbamazepine (74 mg/kg) 4 hours beforeadmission.

Carbamazepine was withdrawn. Urine analysis revealed lowurate excretion based on creatinine levels. Three days aftercarbamazepine withdrawal, the boy’s mental and motorfunction improved, while his serum urate level returnedtowards normal. He was discharged after 7 days’ admission.

At last follow-up, the boy was receiving his usual dose ofcarbamazepine. He remained free of carbamazepine-relatedtoxic symptoms, and his serum uric acid level remainednormal.

Author comment: "We now report, up to our knowledge,the first case of [carbamazepine] overdose, in a patientpresenting with delirium and cyclic coma, accompanied byisolated hypouricemia . . . use of the Naranjo adverse drugreactions probability Scale confirmed a probable relationshipbetween the hypouricemia and [carbamazepine] overdose inthis patient".Ahmed M, et al. Hypouricemia in association with carbamazepine overdose.Journal of Pediatric Epilepsy 1: 65-67, No. 1, 2012. Available from: URL: http://dx.doi.org/10.3233/PEP-2012-010 - United Kingdom 803086075

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Reactions 27 Apr 2013 No. 14490114-9954/10/1449-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved