Therapeutic monitoring of antiepileptic drugs. I--Clinical aspects.

The management of epilepsy has been markedly improved during the last twenty years, although no new drug has been developed. These therapeutic advantages have been made possible by applying the concept of "therapeutic range" of antiepileptic drugs. This range was the result of some pioneer studies showing a good relationship between clinical effects and drug concentrations. Today, the approach to the drug therapy of epilepsy is heavily dependent on the application of this concept. Infact, important factors as patient compliance, variability in drug bioavailability and drug metabolism, drug interactions, disease interactions, etc, that may influence the clinical effect of a given dose, may be controlled by regular monitoring of antiepileptic drugs. However, the concept of "therapeutic range" should not be applied mechanically to patient treatment. The best results are obtained when the analytical results, the therapeutic situation and the clinical status of the patient are considered together. In this case, an important improvement of the quality of life of the epileptic patients can be reached.