Mephenytoin

Mephenytoin
Mephenytoin
Systematic (IUPAC) name
5-ethyl-3-methyl-5-phenyl-imidazolidine-2,4-dione
Clinical data
AHFS/Drugs.com Micromedex Detailed Consumer Information
MedlinePlus a611020
Pregnancy cat. C(US)
Legal status  ?
Routes Oral
Pharmacokinetic data
Half-life 7 hours
Identifiers
CAS number 50-12-4 YesY
ATC code N03AB04
PubChem CID 4060
DrugBank APRD00512
ChemSpider 3920 YesY
UNII R420KW629U YesY
KEGG D00375 YesY
ChEMBL CHEMBL861 YesY
Chemical data
Formula C12H14N2O2 
Mol. mass 218.252
SMILES eMolecules & PubChem
 N(what is this?)  (verify)

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.

Mephenytoin is no longer available in the US or the UK. It is still studied largely because of its interesting hydroxylation polymorphism.

References