Dilantin side effects can mean that physical tasks become difficult.  Symptoms like Cerebellar atrophy, ataxia cerebellar atrophy, cerebellar shrinking, Dilantin cerebral atrophy, cerebral degeneration, and cerebral cortical atrophy.

High Dilantin symptoms Studies

The therapeutic range is 10-20 mcg/mL. Total phenytoin levels (mcg/mL) and typical corresponding signs and symptoms are as follows:

Between 10 and 20 - Occasional mild nystagmus

Between 20 and 30 - Nystagmus

Between 30 and 40 - Ataxia, slurred speech, nausea, and vomiting

Between 40 and 50 - Lethargy and confusion

Higher than 50 - Coma and seizures

However, the predictive performance of such formulas has been called into question.