About topiramatea sulfamate-substituted monosaccharide, carbonic anhydrase inhibitor, anticonvulsant,antimigraine.mechanism of action of topiramatetopiramate acts on the motor cortex where it stabilizes neuronal membrane and inhibits the spread of seizure discharge. it prolongs the inactivated state of voltage sensitive neuronal sodium ion channel either by increasing the efflux or decreasing the influx of sodium ion across the cell membrane and inhibits the high frequency neuronal discharge. it enhances the inhibitory neurotransmitter gaba and inhibits the excitatory glutamate receptors. topiramate is also used in migraine prophylaxis. topiramate also has weak carbonic anhydrase inhibitory activity.