A 7-year-old child has absence seizures occurring 20–30 times a day. EEG shows 3 Hz generalised spike-wave discharges. Neurological examination is normal. The first-line antiepileptic drug of choice is:
- A Carbamazepine
- B Ethosuximide ✓
- C Phenytoin
- D Phenobarbitone
Correct answer: B. Ethosuximide
Explanation
Ethosuximide is the drug of choice for pure childhood absence epilepsy (CAE) without tonic-clonic seizures; it inhibits T-type calcium channels in thalamic neurons that generate the 3 Hz spike-wave rhythm. Valproate is equally effective but has a higher side-effect profile; sodium valproate is preferred when absence seizures co-exist with generalised tonic-clonic seizures. Carbamazepine and phenytoin are contraindicated in absence epilepsy as they can exacerbate absence or myoclonic seizures. Phenobarbitone is not effective for absence.
Reference: Ghai Essential Pediatrics, 10th ed.
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Written and medically reviewed by the StethoPrep medical team.