 Acetyl-L-carnitine lowers hyperammonemia less markedly than L-carnitine.Although the mechanism of action of valproate is not fully understood, traditionally, its anticonvulsant effect has been attributed to the blockade of voltage-gated sodium channels and increased brain levels of gamma-aminobutyric acid (GABA).The GABAergic effect is also believed to contribute towards the anti-manic properties of valproate.