Phenytoin is an anticonvulsant drug used in the prophylaxis and control of various types of seizures. Phenytoin is classified as a hydantoin derivative and despite its narrow therapeutic index, it is one of the most commonly used anticonvulsants.
- Mechanism
- Curator reviewed · 6 references
Although phenytoin first appeared in the literature in 1946, it has taken decades for the mechanism of action to be more specifically elucidated. Although several scientists were convinced that phenytoin altered sodium permeability, it wasn’t until the 1980’s that this phenomenon was linked to voltage-gated sodium channels.
Phenytoin is often described as a non-specific sodium channel blocker and targets almost all voltage-gated sodium channel subtypes. More specifically, phenytoin prevents seizures by inhibiting the positive feedback loop that results in neuronal propagation of high frequency action potentials.
- Primary indication
- Phenytoin is indicated to treat grand mal seizures, complex partial seizures, and to prevent and treat seizures during or following neurosurgery.Curator reviewed · 15 structured indications
- Formula / weight
- C15H12N2O2 · 252.268 g/mol (avg)
- First approval
- Canada, 2004 · United States, 1953
- Also known as
- 5,5-Diphenylhydantoin · Diphenylhydantoin · Phentytoin · PR-122 (redox-phenytoin) · Redox-phenytoin
- Code names
- NSC-8722 · PR-122
- Brand names
Resolves to
CXOFVDLJLONNDW-UHFFFAOYSA-NSMILESO=C1NC(=O)C(N1)(C1=CC=CC=C1)C1=CC=CC=C1What you can answer from here — as of September 23, 2026
Which drugs share a target with Phenytoin, and which of those have an active Phase 3 trial?
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