Name: Phenytoin (Dilantin)
Class: Antiepileptic Agent (Tonic-Clonic/Complex-Partial)
Mechanism: Blocks voltage-dependent Na+ channels ® inhib. of sustained high-freq repetitive neuron firing.
Absorption:
Dist.: 69-96% protein binding.
Metabolism.:
Excretion, t½: 10-34 hr (adults), 5-140 hr (kids).
Toxicity/S.E.s: Dose-related—nystagmus, cognitive impairment, incoordination, dyskinesias, seizure exacerbation. Non-dose-related—hirsutism, coarsening of facial features, exacerbation of acne, gingival hyperplasia, osteopenia, neuropathy, folate deficiency anemia. Idiosync.—allergic dermatitis, fetal drug effects, hepatic failure, serum sickness rxn, SLE-like rxn, hyperglycemia, aplastic anemia, granulocyte suppression. Drug interactions ( w/carbamazepine, felbamate; ¯ w/valproic acid).
Utility: A DOC for generalized tonic-clonic seizures. A DOC for 1° & 2° generalized partial and complex-partial seizures.
Special Features: