Which medication is the first-line treatment for absence seizures?

Which medication is the first-line treatment for absence seizures?

• A. Ethosuximide
• B. Valproic acid
• C. Lamotrigine
• D. Levetiracetam

Answer: (A)

Absence seizures arise from thalamocortical circuits and are driven by bursts of activity mediated by T-type calcium channels in the thalamus. Ethosuximide directly inhibits these T-type calcium channels, dampening the burst firing that produces the characteristic 3 Hz spike-and-wave pattern. This targeted mechanism makes ethosuximide especially effective for pure absence seizures and generally well tolerated, so it is the preferred first-line therapy when the clinical picture is limited to absence seizures. Other drugs can help broader or different seizure types, but they aren’t as specifically effective for absence. Valproic acid works for a wide range of generalized seizures but carries greater risks like hepatotoxicity and teratogenicity. Lamotrigine and levetiracetam can be used for several seizure types but are not as reliably first-line for absence when used alone.

Absence seizures arise from thalamocortical circuits and are driven by bursts of activity mediated by T-type calcium channels in the thalamus. Ethosuximide directly inhibits these T-type calcium channels, dampening the burst firing that produces the characteristic 3 Hz spike-and-wave pattern. This targeted mechanism makes ethosuximide especially effective for pure absence seizures and generally well tolerated, so it is the preferred first-line therapy when the clinical picture is limited to absence seizures.

Other drugs can help broader or different seizure types, but they aren’t as specifically effective for absence. Valproic acid works for a wide range of generalized seizures but carries greater risks like hepatotoxicity and teratogenicity. Lamotrigine and levetiracetam can be used for several seizure types but are not as reliably first-line for absence when used alone.