Toxic effects of lamotrigine ingestion in children

Lamotrigine (LTG) is a relatively new antiepileptic drug. There is only few information available about toxic effects in children.

Patient 1: A two year and five month old girl was admitted three hours after swallowing one tablet of 200mg of LTG. She showed vomitting, behavioural changes, agitation and somnolence. Clinically we saw an agitated child with atactic athetotic movements, tremor and aggressive behaviour. Laboratory investigations were unremarkable apart from slightly elevated liver enzymes. LTG-level was 27.7mg/l (normal range 3–14mg/l). After unsuccessful trials of benzodiazepines neuroleptic treatment with levomepromazine was initiated with remarkable improvement of the behavioural and motor symptoms. Under symptomatic therapy and monitoring liver values came back to normal and LTG level was falling within 24 hours. She could be discharged the following day.

Patient 2: An one year and eleven month old boy was admitted after two first generalized seizures. On admittance he was somnolent and showed atactic movements with tremor and nystagm. Initially encephalitis was suspected. Only after 24 hours his mental and neurological status normalised. After another specific interrogation LTG ingestion was suspected. Plasma level was measured in high therpeutic range with 14.7mg/l.

Conclusion: LTG-intoxications are seldom in children. We report on two cases in otherwise healthy children. Main symptoms were behavioural changes, extrapyramidal motor signs and epileptic seizures. Plasma levels were not correlating with clinical severity. Symptomatic therapy and intensiv monitoring seem to be most important. Administration of activated charcoal and gastric lavage should be considered in special cases. We recognised marked improvement of symptoms with neuroleptic treatment with levomepromazine in one case, which we explain with antipsychotic and anticholinergic effects on the extrapyramidalmotoric system.