Mechanisms of action of phenytoin
In chemical structure, phenytoin is related to the barbiturates.
The mechanism of action is not definitely known, but extensive research strongly suggests that its main mechanism is to block frequency-, use- and voltage-dependent neuronal sodium channels, and therefore limit repetitive firing of action potentials.
At usual levels, there is little or no change in normal patterns of firing. At high or toxic levels, however, phenytoin can impair the function of healthy neurons.
