[The status of plasma level determination of anticonvulsants]

Based on pharmacologic-pharmacokinetic data a critical synopsis of the role of anticonvulsant plasma level determinations in the treatment of epilepsy is given. The analytical methods themselves and the validity of the so called therapeutic range are evaluated in general as well as for the particular antiepileptic drugs. Whereas plasma levels of phenytoin play an important role in therapeutic management they are without major relevance in the therapy with clonazepam and other benzodiazepines. Determinations of anticonvulsant concentrations can be of help in certain circumstances of therapeutic decisions, but uncritical usage as a routine method has to be discouraged. So far, prospective studies were not able to proof a general advantage of this method in the management of epileptic patients.