|AHFS/Drugs.com||Consumer Drug Information|
|By mouth (tablets)|
|Elimination half-life||3–9 hours|
|CompTox Dashboard (EPA)|
|Chemical and physical data|
|Molar mass||204.225 g/mol g·mol−1|
|3D model (JSmol)|
Similar to phenytoin.
Ethotoin is indicated for tonic-clonic and partial complex seizures.
Ethotoin is available in 250 mg tablets. It is taken orally in 4 to 6 divided doses per day, preferably after food.
Ethotoin, 3-ethyl-5-phenylimidazolidine-2,4-dione, is synthesized by the reaction of benzaldehyde oxynitrile, with urea or ammonium hydrocarbonate, which forms an intermediate urea derivative which on acidic conditions cyclizes to 5-phenylhydantoin. Alkylation of this product using ethyliodide leads to the formation of ethotoin.