Supervision of epileptic patients taking phenytoin

Serum phenytoin concentrations in outpatients and inpatients with epilepsy have been contrasted. Individual patients were receiving prescriptions ranging from 100 to 300 mg. of sodium phenytoin daily, but the two groups were comparable in respect of dosage, age, and sex distribution. Whereas the mean phenytoin concentration among 14 inpatients was 28 mug./ml. that among 15 outpatients was only 15.7 mug./ml. When the supervision of a further 12 outpatients was changed to include more frequent visits and regular provision of blood samples their mean serum concentration of phenytoin rose from 17.5 to 27.7 mug./ml.The results indicate that failure to follow dosage instructions is a factor of major importance among epileptic patients whose response to treatment is inadequate or erratic.