[Optimizing the therapeutic process in long-term antiepileptic therapy through the determination of drug levels in patients].

Serum levels of phenytoin, phenobarbital, carbamazepine, and ethosuximide were determined in about 2,000 subjects treated on an outpatient and inpatient basis, respectively. Therapeutical serum level ranges were obtained in about 50 percent of the patients. In the other patients, the values determined were either too low or too high. These studies, in addition to enabling the drug-taking behavior of patients to be objectified, made possible "blood-level-oriented dosage" and allowed differential approaches to be adopted in the control of undesirable effects. Blood level determinations permit the therapeutical procedure to be improved and made more reliable especially in "problem cases". A pharmacokinetic therapy service has proved useful for long-time antiepileptic therapy.