mephenytoin: a toxic anticonvulsant drug (trade name Mesantoin) used in the treatment of epilepsy when less toxic anticonvulsants have been ineffective
anticonvulsant: a drug used to treat or prevent convulsions (as in epilepsy)
facilitation: (neurophysiology) phenomenon that occurs when two or more neural impulses that alone are not enough to trigger a response in a neuron combine to trigger an action potential