Ethosuximide

Ethosuximide
Clinical data
Trade names	Zarontin, others
AHFS/Drugs.com	Monograph
MedlinePlus	a682327
License data	US DailyMed: Ethosuximide;
Pregnancy; category	AU: D;
Routes of; administration	By mouth (capsules, solution)
ATC code	N03AD01 (WHO) ;
Legal status
Legal status	BR: Class C1 (Other controlled substances); US: ℞-only; EU: Rx-only; In general: ℞ (Prescription only);
Pharmacokinetic data
Bioavailability	93%
Metabolism	liver (CYP3A4, CYP2E1)
Elimination half-life	53 hours
Excretion	kidney (20%)
Identifiers
	IUPAC name (RS)-3-Ethyl-3-methyl-pyrrolidine-2,5-dione;
CAS Number	77-67-8 ;
PubChem CID	3291;
IUPHAR/BPS	7182;
DrugBank	DB00593 ;
ChemSpider	3175 ;
UNII	5SEH9X1D1D;
KEGG	D00539 ;
ChEBI	CHEBI:4887 ;
ChEMBL	ChEMBL696 ;
CompTox Dashboard (EPA)	DTXSID7023019 ;
ECHA InfoCard	100.000.954
Chemical and physical data
Formula	C7H11NO2
Molar mass	141.170 g·mol−1
3D model (JSmol)	Interactive image;
Chirality	Racemic mixture
Melting point	64 to 65 °C (147 to 149 °F)
	SMILES O=C1NC(=O)CC1(C)CC;
	InChI InChI=1S/C7H11NO2/c1-3-7(2)4-5(9)8-6(7)10/h3-4H2,1-2H3,(H,8,9,10) ; Key:HAPOVYFOVVWLRS-UHFFFAOYSA-N ;
	(verify)

Ethosuximide, sold under the brand name Zarontin among others, is a medication used to treat absence seizures. It may be used by itself or with other antiseizure medications such as valproic acid. Ethosuximide is taken by mouth.

Ethosuximide is usually well tolerated. Common side effects include loss of appetite, abdominal pain, diarrhea, and feeling tired. Serious side effects include suicidal thoughts, low blood cell levels, and lupus erythematosus. It is unclear if it has adverse effects on the fetus during pregnancy. Ethosuximide is in the succinimide family of medications. Its mechanism of action is thought to be due to antagonism of the postsynaptic T-type voltage-gated calcium channel.

Ethosuximide was approved for medical use in the United States in 1960. It is on the World Health Organization's List of Essential Medicines. Ethosuximide is available as a generic medication. As of 2019, its availability was limited in many countries, with concerns about price fixing in the United States.