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
- Shorvon SD, Fish DR, Perucca E, Dodson WE, eds. (2004). The Treatment of Epilepsy. Blackwell Publishing. ISBN 0-632-06046-8.
- Resor SR (1991). The Medical Treatment of Epilepsy. Marcel Dekker. ISBN 0-8247-8549-5.
- "Mephenytoin". The Comparative Toxicogenomics Database.