Pharmaceutical compositions comprise as the active ingredient potent orally active, nonneurotoxic anticonvulsant compounds that are highly effective in the MES animal model and are excitatory amino acid antagonists, and that are selected from the groups of hydrazones, hydrazines and semicarbazones consisting of those of the formulae: ##STR1## wherein R.sup.1 is 4-pyridyl or 3-pyridyl, R.sup.2 is methyl, ethyl or phenyl, R.sup.3 is 3,4-dichloro, p-chloro or m-chloro and R.sup.4 is oxygen. The compositions are administered to mammals in an amount to provide a dosage amount ranging from about 10 mg/kg to 200 mg/kg of body weight.