Ethosuximide

Ethosuximide

Clinical data
Trade names	Zarontin
AHFS/Drugs.com	Monograph
MedlinePlus	a682327
Pregnancy category	AU: D US: C (Risk not ruled out)
Routes of administration	by mouth (capsules, solution)
ATC code	N03AD01 (WHO)
Legal status
Legal status	US: ℞-only In general: ℞ (Prescription only)
Pharmacokinetic data
Bioavailability	93%
Metabolism	liver (CYP3A4, CYP2E1)
Biological half-life	53 hours
Excretion	kidney (20%)
Identifiers
IUPAC name (RS)-3-Ethyl-3-methyl-pyrrolidine-2,5-dione
CAS Number	77-67-8 Y
PubChem CID	3291
IUPHAR/BPS	7182
DrugBank	DB00593 Y
ChemSpider	3175 Y
UNII	5SEH9X1D1D
KEGG	D00539 Y
ChEBI	CHEBI:4887 Y
ChEMBL	CHEMBL696 Y
ECHA InfoCard	100.000.954
Chemical and physical data
Formula	C7H11NO2
Molar mass	141.168 g/mol
3D model (Jmol)	Interactive image
Chirality	Racemic mixture
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) Y Key:HAPOVYFOVVWLRS-UHFFFAOYSA-N Y

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.

Side effects are generally minimal. 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 use during pregnancy or under the age of three is safe for the baby. Ethosuximide is in the succinimide family of medications. How exactly it works is unclear.

Ethosuximide was approved for medical use in the United States in 1960. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Ethosuximide is available as a generic medication. The wholesale cost in the developing world is about 27.77 USD per month. In the United States the wholesale cost as of 2016 is about 41.55 USD per month for a typical dose.

It is approved for absence seizures. Ethosuximide is considered the first choice drug for treating absence seizures in part because it lacks the idiosyncratic hepatotoxicity of the alternative anti-absence drug, valproic acid.

The following can occur with or without bone marrow loss:

Valproates can either decrease or increase the levels of ethosuximide; however, combinations of valproates and ethosuximide had a greater protective index than either drug alone.