NCIt definition : 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.;