Antiepileptics control seizures and are used in epilepsy, trigeminal neuralgia and Lennox-Gastaut syndrome. Sodium channel blockers — phenytoin (IV use in status epilepticus), carbamazepine (first-line for focal seizures — enzyme induction risk), lamotrigine (broad spectrum, good tolerability) and oxcarbazepine (carbamazepine analogue with fewer interactions) — stabilise sodium channels in their inactive conformation. Valproate is a broad-spectrum agent (generalised seizures, absences) but contraindicated in women of childbearing potential (teratogenicity). Eslicarbazepine is an oxcarbazepine derivative. Levetiracetam binds to SV2A protein, modulating neurotransmitter release — broad spectrum, few interactions. Pregabalin and gabapentin bind to the alpha-2-delta subunit of calcium channels — used in neuropathic pain and epilepsy. Topiramate has multiple mechanisms (sodium channel blockade, GABA potentiation, carbonic anhydrase inhibition). Ethosuximide is first-line for absence seizures. (Sources: DailyMed/FDA, EMC-UK/MHRA, ILAE Guidelines)
