What medication is used in the treatment of generalized tonic-clonic seizures and commonly in absence epilepsy?

Ethosuximide is specifically designed for the treatment of absence seizures, which are a common form of generalized seizures characterized by brief lapses in consciousness. It selectively inhibits T-type calcium channels in the thalamic neurons, reducing the burst firing of these neurons that leads to the typical absence seizure activity.

In addition to its primary use for absence epilepsy, ethosuximide can also be part of the treatment strategy for generalized tonic-clonic seizures, although it is less commonly effective for them compared to other medications. It works efficiently to minimize seizures without significantly affecting other types of epilepsy, making it a suitable choice for patients who predominantly experience absence seizures.

This specificity in mechanism and efficacy for absence seizures is what makes ethosuximide the correct answer in this context, allowing it to effectively manage generalized tonic-clonic seizures while primarily targeting absence seizures.