phenytoin
Pronunciation: FEN-i-toyn
An anticonvulsant medication that blocks sodium channels to prevent seizures, commonly used in pediatric epilepsy management.
Full Definition
Phenytoin is a hydantoin-class anticonvulsant that prevents seizures by blocking voltage-gated sodium channels, thereby stabilizing neuronal membrane potential and preventing excessive firing. It is effective for focal and generalized tonic-clonic seizures but not absence seizures. In pediatric neurology, phenytoin requires careful dosing due to nonlinear pharmacokinetics and potential adverse effects including gingival hyperplasia, hirsutism, and coarsening of facial features. Regular monitoring of serum levels is essential to maintain therapeutic efficacy while avoiding toxicity.
Usage
Usage note: Always specify whether referring to phenytoin sodium or free phenytoin when reporting levels.
In Context
- "Phenytoin levels were subtherapeutic, requiring dose adjustment for optimal seizure control." — Laboratory results
- "The patient developed gingival hyperplasia as a side effect of long-term phenytoin therapy." — Adverse reaction report