Absence Seizures (Petit Mal)

Key points

• Absence seizures* (Petit mal) — NICE NG217 (2022, updated January 2025): OFFER ETHOSUXIMIDE FIRST-LINE. The older 'sodium valproate or ethosuximide' teaching is superseded.
• If first-line treatment is unsuccessful, offer a choice of lamotrigine, levetiracetam or sodium valproate as second-line monotherapy or add-on — following MHRA valproate restrictions.
• Ethosuximide blocks T-type calcium channels in thalamic neurons · it does not cover tonic-clonic seizures, so where generalised tonic-clonic seizures coexist an agent covering both is needed.
• Do NOT use carbamazepine, gabapentin, oxcarbazepine, phenytoin, pregabalin, tiagabine or vigabatrin — these may EXACERBATE absence seizures. Myoclonic seizures**