Carbamazepine is not usually used for which type of seizures?

• A. Partial
• B. Tonic-clonic
• C. Myoclonic
• D. Absence

Answer: (D)

Absence seizures involve rapid, generalized thalamocortical oscillations, not a single focal brain region. Carbamazepine works by blocking voltage-gated sodium channels to stabilize membranes and suppress focal hyperexcitability, which makes it effective for partial (focal) seizures and secondary generalized tonic-clonic seizures. However, this mechanism doesn’t address the generalized network dysfunction seen in absence seizures, and in fact sodium channel blockers can worsen or fail to control absence. That’s why carbamazepine is not usually used for absence seizures. For absence, the typical choices are ethosuximide, which targets the T-type calcium channels in the thalamus, with valproic acid as an alternative in some cases.