Ethotoin

Ethotoin
Clinical data
AHFS/Drugs.com	Consumer Drug Information
MedlinePlus	a682022
Pregnancy; category	C;
Routes of; administration	By mouth (tablets)
ATC code	N03AB01 ( WHO );
Pharmacokinetic data
Elimination half-life	3–9 hours
Identifiers
	IUPAC name 3-Ethyl-5-phenyl-imidazolidine-2,4-dione;
CAS Number	86-35-1 ;
PubChem CID	3292 ;
IUPHAR/BPS	7183 ;
DrugBank	DB00754 ;
ChemSpider	3176 ;
UNII	46QG38NC4U ;
KEGG	D00708 ;
ChEBI	CHEBI:4888 ;
ChEMBL	ChEMBL1095 ;
CompTox Dashboard (EPA)	DTXSID6023020 ;
ECHA InfoCard	100.001.514
Chemical and physical data
Formula	C11H12N2O2
Molar mass	204.229 g·mol−1
3D 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) ; Key:SZQIFWWUIBRPBZ-UHFFFAOYSA-N ;
	(verify)

Last updated December 25, 2025

Ethotoin (previously marketed as Peganone) is an anticonvulsant drug used in the treatment of epilepsy.^[1] It is a hydantoin, similar to phenytoin. It is not available in the United States.

Mechanism of action

The mechanism of action of ethotoin is similar to that of phenytoin.^{[ citation needed ]}

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.^[2]

Dosing

Ethotoin is available in 250 mg tablets.^[3]^[4] It is taken orally in 4 to 6 divided doses per day, preferably after food.

Side effects

Side effects include ataxia, visual disturbances, rash, and gastrointestinal problems.^{[ citation needed ]}

Chemistry

Ethotoin is synthesized by the reaction of benzaldehyde oxynitrile (2) with urea or ammonium bicarbonate, which forms an intermediate urea derivative (3) which on acidic conditions cyclizes to 5-phenylhydantoin (4).^[5] Alkylation of this product using ethyl iodide leads to the formation of ethotoin (5).

References

↑ Schwade ED, Richards RK, Everett GM (May 1956). "Peganone, a new antiepileptic drug". Dis Nerv Syst. 17 (5): 155–8. PMID 13317788.
↑ Shorvon, S.D.; Fish, David R.; Perucca, Emilio; Dodson, W. Edwin, eds. (2004). The Treatment of Epilepsy. Blackwell Publishing. ISBN 0-632-06046-8.
↑ "Ethotoin". drugs.com.
↑ "PEGANONE 250 mg Ethotoin Tablets, USP" (PDF).
↑ A. Pinner, Chem. Ber., 21, 2324 (1888); W.J. Close, U.S. patent 2,793,157 (1946)

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[1] Schwade ED, Richards RK, Everett GM (May 1956). "Peganone, a new antiepileptic drug". Dis Nerv Syst. 17 (5): 155–8. PMID 13317788.

[2] Shorvon, S.D.; Fish, David R.; Perucca, Emilio; Dodson, W. Edwin, eds. (2004). The Treatment of Epilepsy. Blackwell Publishing. ISBN 0-632-06046-8.

[3] "Ethotoin". drugs.com.

[4] "PEGANONE 250 mg Ethotoin Tablets, USP" (PDF).

[5] A. Pinner, Chem. Ber., 21, 2324 (1888); W.J. Close, U.S. patent 2,793,157 (1946)

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