• Molecular NamePhenytoin
  • Synonym5,5-diphenylhydantoin; 5,5-Dwufenylohydantoina; Difenilhidantoina [Spanish]; Dihydantoin; Diphenylan Sodium; Diphenylhydantoin; Diphenylhydantoine [French]; Diphenylhydatanoin; DPH; Fenitoina [INN-Spanish]; Phenytoin Sodium; Phenytoine; Phenytoine [INN-French]; Phenytoinum [INN-Latin]
  • Weight252.273
  • Drugbank_IDDB00252
  • ACS_NO57-41-0
  • Show 2D model
  • LogP (experiment)2.47
  • LogP (predicted, AB/LogP v2.0)0.52
  • pka8.3 (25°)
  • LogD (pH=7, predicted)0.52
  • Solubility (experiment)0.0258 mg/ml
  • LogS (predicted, ACD/Labs)(ph=7)-3.27
  • LogSw (predicted, AB/LogsW2.0)0.81
  • Sw (mg/ml) (predicted, ACD/Labs)0.13
  • No.of HBond Donors2
  • No.of HBond Acceptors4
  • No.of Rotatable Bonds2
  • TPSA58.2
  • StatusFDA approved
  • AdministrationOral, parenteral
  • PharmacologyA commonly used antiepileptic. Phenytoin acts to dampen the unwanted, runaway brain activity seen in seizure by reducing electrical conductance among brain cells by stabilizing the inactive state of voltage gated sodium channels. Aside from seizures, it is an option in the treatment of trigeminal neuralgia as well as certain cardiac arrhythmias.
  • Absorption_value90.0
  • Absorption (description)N/A
  • Caco_2-4.57
  • Bioavailability90.0
  • Protein binding89.0
  • Volume of distribution (VD)0.64 L/kg
  • Blood/Plasma Partitioning ratio (D_blood)N/A
  • MetabollsmMetabolized predominantly by CYP2C9 (polymorphic) and also by CYP2C19 (polymorphic); exhibits saturable kinetics with therapeutic doses.
  • Half life6~24 h
  • ExcretionPrimarily through the bile, urinary
  • Urinary Excretion2
  • CleranceVmax = 5.9 +/- 1.2 mg.kg-1.day-1
  • ToxicitySymptoms of overdose include coma, difficulty in pronouncing words correctly, involuntary eye movement, lack of muscle coordination, low blood pressure, nausea, sluggishness, slurred speech, tremors, and vomiting.
  • LD50 (rat)LD50=1635 mg/kg
  • LD50 (mouse)LD50=150 mg/kg