ethotoin ethotoin ethotoin (previously marketed as peganone) is an anticonvulsant drug used in the treatment of epilepsy. it is a hydantoin, similar to phenytoin. it is not available in the united states. ethotoinclinical dataahfs/drugs.comconsumer drug informationmedlineplusa682022pregnancycategory c routes ofadministrationby mouth (tablets)atc coden03ab01 (who) pharmacokinetic dataelimination half-life3–9 hoursidentifiers iupac name 3-ethyl-5-phenyl-imidazolidine-2,4-dione cas number86-35-1 ypubchem cid3292iuphar/bps7183drugbankdb00754 ychemspider3176 yunii46qg38nc4ukeggd00708 ychebichebi:4888 ychemblchembl1095 ycomptox dashboard (epa)dtxsid6023020 echa infocard100.001.514 chemical and physical dataformulac11h12n2o2molar mass204.229 g·mol−13d model (jsmol)interactive image smiles o=c2nc(c1ccccc1)c(=o)n2cc inchi inchi=1s/c11h12n2o2/c1-2-13-10(14)9(12-11(13)15)8-6-4-3-5-7-8/h3-7,9h,2h2,1h3,(h,12,15) ykey:szqifwwuibrpbz-uhfffaoysa-n y (verify) mechanism of action similar to phenytoin. approval history 1957 peganone was granted food and drug administration (fda) approval to abbott laboratories for treatment of grand mal (tonic clonic) and partial complex (psychomotor) seizures. 2003 peganone was acquired from abbott laboratories by ovation pharmaceuticals (specialty pharmaceutical company who acquire underpromoted branded pharmaceutical products). 2018 it was announced by recordati rare diseases inc. that due to a combination of low product demand and complex manufacturing difficulties, product manufacturing, distribution and sale was being discontinued. indications and usage ethotoin is indicated for tonic-clonic and partial complex seizures. dosing ethotoin is available in 250 mg tablets. it is taken orally in 4 to 6 divided doses per day, preferably after food. side effects ataxia, visual disturbances, rash and gastrointestinal problems. chemistry 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. a. pinner, chem. ber., 21, 2324 (1888); w.j. close, u.s. patent 2,793,157 (1946).