Carnitine deficiency in epilepsy: Risk factors and treatment.

Numerous studies have shown that plasma carnitine levels are significantly lower in patients taking valproate than in controls. Free carnitine deficiency is not uncommon in these patients and also occurs in newborns with seizures and in patients taking other anticonvulsant drugs. Carnitine deficiency in epilepsy results from a variety of etiologic factors including underlying metabolic diseases, nutritional inadequacy, and specific drug effects. The relationship between carnitine deficiency and valproate-induced hepatotoxicity is unclear. Carnitine treatment does not always prevent the emergence of serious hepatotoxicity, but it does alleviate valproate-induced hyperammonemia. These studies suggest that specific risk factors for carnitine deficiency can be identified. Preliminary data suggest that carnitine treatment may benefit high-risk, symptomatic patients and those with free carnitine deficiency. Carnitine treatment is not likely to benefit low-risk, asymptomatic patients and those with normal carnitine levels.