Electroencephalography and phenytoin toxicity in mentally retarded epileptic patients

There were significantly more diffuse and focal electroencephalographic abnormalities in 127 mentally retarded epileptic patients treated with phenytoin than in 68 epileptics without phenytoin. Phenytoin intoxication made the difference still more pronounced. Monitoring drug levels and electroencephalograms appears to be the method of choice for ensuring safe and effective medication in intractable epilepsy.