mephenytoin

Mephenytoin is a hydantoin derivative anticonvulsant and antiepileptic drug that was primarily used for the treatment of refractory partial epilepsy and various types of seizures including tonic-clonic (grand mal), psychomotor, focal, and jacksonian-type partial seizures in patients unresponsive to less toxic agents. Its primary site of action appears to be the motor cortex where it inhibits the spread of seizure activity—likely by promoting sodium efflux from neurons and stabilizing neuronal membranes against hyperexcitability. The main mechanism is believed to be blockade of frequency-, use-, and voltage-dependent neuronal sodium channels which limits repetitive firing of action potentials. It is metabolized mainly by CYP2C19. A significant metabolite is nirvanol (which itself has notable toxicity). Due to its risk profile—including potentially fatal blood dyscrasias—mephenytoin has been discontinued in many countries including the US and UK but remains studied for its pharmacogenetic properties[1][2][3][7].

Brand names

Mesantoin

Other names

MethoinMethylphenetoinPhenantoinEpiazinMethyl hydantoinInsultonSedantoinSedantoinalTriantoinMetydanSacernoFenantoin5-Ethyl,3-methyl,5-phenyllmidazolidine,2,4-dioneEpilanPhenylethylmethylhydantoinMephenytoinumMefenitoinaMephenytoineMesontoin3-EthylnirvanolmephentoinMephenetoinum(+/-)-Mephenytoin2,4-Imidazolidinedione, 5‑ethyl‑3‑methyl‑5‑phenyl-5-Ethyl‑3-methyl‑5‑phenylhydantoin3-Methyl–5,5–phenylethylhydantion3-Methyl–5–ethyl–5–phenylhydantion[6]