TOPADAY contains topiramate. The action potentials elicited repetitively by a sustained depolarization of the neurons are blocked by topiramate. Y-aminobutyrate (GABA) activates GABA receptors, and enhances the ability of GABA to induce a flux of chloride ions into neurons. It antagonizes the ability of kainite to activate the kainite/AMPA subtype of excitatory amino acid (glutamate) receptor.