Mephenytoin

**Semantic type:** Pharmacologic Substance

**Definition:** A heterocyclic organic compound with anticonvulsant property. Although the mechanism of action is not well established, mephenytoin potentially promotes sodium efflux from neurons in motor cortex, and stabilizes the threshold against hyperexcitability caused by excessive stimulation. Thus this agent reduces the membrane sodium gradient and prevents cortical seizure signal spreading. It may cause blood dyscrasias, therefore, this agent was only used after other less toxic anticonvulsants had failed.

**Synonyms:** - 2,4-Imidazolidinedione, 5-ethyl-3-methyl-5-phenyl- - 3-Ethylnirvanol - 3-Methyl-5,5-phenylethylhydantoin - MEPHENYTOIN