Mephenytoin (marketed as Mesantoin by Novartis) is a hydantoin, used as an anticonvulsant. It was introduced approximately 10 years after phenytoin, in the late 1940s. The significant metabolite of mephenytoin is nirvanol (5-ethyl-5-phenylhydantoin), which was the first hydantoin (briefly used as a hypnotic). However, nirvanol is quite toxic and mephenytoin was only considered after other less toxic anticonvulsants had failed. It can cause potentially fatal blood dyscrasia in 1% of patients.

CAS：50-12-4
中文别名：5-乙基于-3-甲基-5-苯基乙内酰脲;(±)-Mephenytoin;美芬妥因;
英文别名：Phenantoin;MEPHENYTOIN;mephenytoine;Methoin;Insulton;Triantoin;Mesantoin;5-ethyl-3-methyl-5-phenylhydantoin;Sedantoinal;methyl Hydantoin;Mephenytoin;Methylphenetoin;Epiazin;Sedantoin;
分子式：C12H14N2O2
分子量：218.252
精确质量：218.106
Psa：49.41
Logp：1.7402

MDL号：MFCD00022407

密度：1.154g/cm3
熔点：135-138ºC
储存条件：2-8ºC

安全说明：S26
WGK Germany：2
危险类别码：R22; R36/37/38
海关编码：2933990090
危险品标志：Xn

生产方法
由苯丙酮环合、甲基化而得。 该品为抗癫痫病。大鼠腹腔注射LD50为270mg/kg。
用途
该品为抗癫痫病。大鼠腹腔注射LD50为270mg/kg。