Pharmacology of diphenylhydantoin and carbamazepine action on voltage-sensitive sodium channels

5,5-Diphenylhydantoin or phenytoin (DPH) and carbamazepine (CBZ) are now considered the drugs of choice in the management of grand mal and psychomotor (partial or temporal lobe) epilepsy. It has been suggested that DPH and CBZ may exert their anticonvulsant effects by interacting with voltage-sensitive sodium channels responsible for action potential generation and/or enhancing inhibitory synaptic transmission at synapses that use gamma -aminobutyric acid (GABA) as a neurotransmitter. The present review examines the possible contribution of these effects in raising seizure threshold.