ChEBI: Ethosuximide is a dicarboximide that is pyrrolidine-2,5-dione in which the hydrogens at position 3 are substituted by one methyl and one ethyl group. An antiepileptic, it is used in the treatment of absence seizures and may be used for myoclonic seizures, but is ineffective against tonic-clonic seizures. It has a role as an anticonvulsant and a calcium channel blocker. It is a pyrrolidinone and a dicarboximide.NCI Thesaurus (NCIt): Ethosuximide is a succinimide with anticonvulsant activity. The exact mechanism of action is not entirely understood, but most likely ethosuximide exerts its effects by partial antagonism of T-type calcium channels of the thalamic neurons. This leads to a decrease in burst firing of thalamocortical neurons, which stabilizes the nerve activity in the brain and prevents seizures.