Lamotrigine-induced tourettism

Background: Lamotrigine (LTG) has a broad spectrum of antiepileptic efficac y and generally benign side effects except for idiosyncratic rashes. Object ive: Three children are described in whom LTG caused dose-related Tourette syndrome (TS) symptoms. Although undoubtedly rare, this interesting phenome non supports the mounting evidence in favor of the multifactorial genesis o f TS symptoms. Results: The main known antiseizure mechanism of LTG is to b lock excessive presynaptic release of excitatory amino acids (EAAs), which occurs when there are sustained neuronal burst firings, as happens within e pileptogenic brain tissue. LTG does not prevent the spontaneous release of EAAs and thus does not affect their normal functions. Conclusions: Among th e many proposed explanations for the pathogenesis of TS is the dopamine hyp othesis: a dysfunction in dopamine uptake in the striatum. EAAs can also in terfere with striatal dopamine uptake. Conceivably, LTG may cause TS sympto ms by failing, at high doses, to regulate the presynaptic release of EAAs i n the striatum properly.