[The clinical interpretation of the concentrations of anticonvulsants in the blood].

Determination of antiepileptic drug serum levels is today one of the most helpful aids in epilepsy therapy. Reference to "therapeutic ranges" should be abstained from the individual case where they are, at best, useless, but often misleading. The most important determinations are those immediately following a seizure because they are indispensible to establish the individual therapeutic threshold, and to elucidate the causes of seizure relapse. A further important purpose is the definition of the individual pharmacokinetics as a guide to changes of dose.