Interactions between folates and carbamazepine or valproate in the rat

Carbamazepine and valproate each afforded protection against seizures induced by electroshock or by inhalation of hexafluorodiethyl ether (HFDE). After injections of either anticonvulsant for 10 days, plasma folate concentration decreased, but brain folate concentration did not change. Folinic acid administration had no effect on the concentration of either anticonvulsant in plasma or brain. These findings are in contrast with the demonstrated effects of other anticonvulsants on folate biochemistry.