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 category	US: C (Risk not ruled out)
Routes of administration	Oral
Pharmacokinetic data
Biological half-life	7 hours
Identifiers
CAS Number	50-12-4
ATC code	N03AB04 (WHO)
PubChem	CID 4060
IUPHAR/BPS	7223
DrugBank	DB00532
ChemSpider	3920
UNII	R420KW629U
KEGG	D00375
ChEMBL	CHEMBL861
Chemical data
Formula	C12H14N2O2
Molar mass	218.252
SMILES O=C2N(C(=O)NC2(c1ccccc1)CC)C
InChI InChI=1S/C12H14N2O2/c1-3-12(9-7-5-4-6-8-9)10(15)14(2)11(16)13-12/h4-8H,3H2,1-2H3,(H,13,16) Key:GMHKMTDVRCWUDX-UHFFFAOYSA-N
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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

• The Treatment of Epilepsy edited by S. D. Shorvon, David R. Fish, Emilio Perucca, W. Edwin Dodson. Blackwell Publishing. 2004. ISBN 0-632-06046-8
• The Medical Treatment of Epilepsy by Stanley R Resor. Published by Marcel Dekker (1991). ISBN 0-8247-8549-5.
• The Comparative Toxicogenomics Database: Mephenytoin