Generic substitution for brand name antiepileptic drugs: a survey

There are presently 26 different generic preparations for five brand name antiepileptic drugs (AEDs) on the Canadian market with others likely to be released in the near future. The purpose of this review is to examine the basis for the controversy surrounding generic substitution for brand name antiepileptic drugs, to present the results of a survey of neurologists' and patients' attitudes toward generic substitution and to increase neurologists' awareness of the issues.

The current federal and provincial regulations pertaining to generic drug approval and substitution are reviewed. Published anecdotal and survey reports of the effectiveness and tolerability of generic substitution for AEDs are reviewed. A pilot questionnaire survey of 83 patients from four adult epilepsy clinics and 46 neurologists from across Canada was undertaken to determine attitudes toward generic substitution.

Several authors have suggested that some AEDs, particularly those with a narrow therapeutic index, may pose problems with generic substitution. Although generic AEDs are lower in price, possible increased side effects and morbidity and the need for closer monitoring could partially offset the cost savings. The results of our survey highlight significant unawareness of the process of generic substitution among both patients and neurologists and reveal a general level of discomfort among neurologists to prescribe generic AEDs. Further data should be obtained about the potential consequences of generic substitution in epilepsy patients.