苯妥英抑制劑Phenytoin?is a?hydantoin?derivative and a non-sedative antiepileptic agent with anticonvulsant activity.?Phenytoin?potentially acts by promoting?sodium?efflux from neurons located in the motor cortex reducing post-tetanic potentiation at synapses. The reduction of potentiation prevents cortical seizure foci spreading to adjacent areas, stabilizing the threshold against hyperexcitability. In addition, this agent appears to reduce sensitivity of muscle spindles to stretch causing muscle relaxation.