Phenytoin (brand name Dilantin) is an anticonvulsant or antiepileptic medication used to treat and prevent generalized tonic-clonic seizures.
To determine the level of the drug phenytoin in your blood in order to maintain a therapeutic level and to detect potential for toxicity.
The therapeutic ranges for adults taking phenytoin have been established at 10.0-20.0 mcg/mL for total phenytoin (bound plus unbound) and 1.0-2.0 mcg/mL for free phenytoin (unbound only). The range for percent free phenytoin is 8-14%.
