Effects of phenobarbital on plasma concentration of phenytoin and mortality of mice treated with phenytoin after electroshock.

THe effects of phenobarbital on the plasma concentration of phenytoin and mortality of the phenytoin-treated mice were mainly studied. The plasma concentration of phenytoin estimated in the live mice after electroshock was significantly higher than that in the dead mice, suggesting that biological activity of phenytoin is dependent on its plasma concentration where individual difference seems to be large. Though the pretreatment of mice with phenobarbital lowered the plasma concentration of phenytoin, all the mice were alive after electroshock with further treatment with phenobarbital and phenytoin. These results suggest that combination of phenobarbital with phenytoin for the treatment of epileptic patients may be feasible.