Hydantoin is another name for which antiseizure medication?

• A. Phenytoin
• B. Valproic acid
• C. Lamotrigine
• D. Gabapentin

Answer: (A)

Hydantoin denotes the class of antiseizure drugs that includes phenytoin as its primary example. Phenytoin is the drug most traditionally described as a hydantoin. It works by stabilizing neuronal membranes through prolongation of the inactivated state of voltage-gated sodium channels, which reduces high-frequency firing and the spread of seizures. It’s commonly used for generalized tonic-clonic seizures and focal seizures, and has historical use in status epilepticus. Other drugs listed are not hydantoins: valproic acid has multiple mechanisms and is not in this class, lamotrigine is a different sodium-channel blocker with distinct pharmacology, and gabapentin acts mainly on the alpha-2-delta subunit of calcium channels.