Monitoring of diphenylhydantoin (DPH) serum level has become a subject of clinical interest for it's usefulness in detecting noncompliance, confirming suspected intoxication, evaluating inadequate control of seizure, and in determining the appropriate...
Monitoring of diphenylhydantoin (DPH) serum level has become a subject of clinical interest for it's usefulness in detecting noncompliance, confirming suspected intoxication, evaluating inadequate control of seizure, and in determining the appropriate dosage.
Sometimes ignorant uses of DPH have brought in difficulties in proper management of the epileptics before the close of 1970's in Korea, when the monitoring of the serum level became available and few reports have been published. The authors tried to investigate 100 epileptics, who have maintained DPH in Kyung Hee University Hospital, to confirm the serum levels of DPH in relation to daily dosage, dosage based on body weight, response to maintenance therapy, and toxic effects. And the following results were obtained.
1. The mean serum levels of the adult patients were 12.4±12.2㎍/ml in a group with DPH 200mg daily and 12.3±7.6㎍/ml with 300mg daily, 10.6±10.1㎍/ml in a group with 4-4.9mg/kg/day, 12.3±6.3㎍/ml with 5-5.9mg/kg/day, 12.4±6.7㎍/ml with 6-6.9mg/kg/day.
2. Among the patients with 300mg daily, the mean serum level was 10.4±8.0㎍/ml in a group with 4-4.9mg/kg/day and 12.7±6.1㎍/ml with 5-5.9mg/kg/day based on body weight.
3. About 45% were controlled completely with DPH maintenance below the level of 9.9㎍/ml, 26% in the range of 10-19.9㎍/ml and the mean serum level of the patients who were controlled completely was 10.2±8.5㎍/ml. So the serum levels could not be regarded as an absolute indicator of clinical efficacy in DPH maintenance.
4. Nystagmus and ataxia were noticed in 4 patients and the serum levels were below effective therapeutic range in 2 patients among them.