Pharmacoresistance: Modern Concept and Basic Data Derived from Human Brain Tissue.

Multiple studies have established that approximately one third of patients with epilepsy have seizures that cannot be controlled satisfactorily with antiepileptic drugs (AEDs), but the data have not conclusively determined whether pharmacoresistance develops as a result of the disease process or exists at the time of the initial seizure. The mechanism by which it occurs has not been firmly established, although it is believed to be a multifactorial process. Evidence suggests that drug resistance is present in the early stage of the disease, a concept that is potentially beneficial to patients. The rationale for the concept of pharmacoresistance is clear from both a clinical and scientific perspective. Greater emphasis on identifying the AED most suited to the particular patient on the first attempt, when the likelihood of achieving seizure control is greatest, is one possible consequence.