Controversy persists whether generic antiepileptic drugs (AEDs) are interchangeable with brand name drugs with respect to efficacy and adverse events. Three hundred and one neurologists responded to a survey regarding generic AEDs mailed to 6420 neurologists, for an overall response rate of 4.7%. One hundred and ninety-six (67.8%) neurologists reported breakthrough seizures after a switch from a brand name to generic AED; 93 (32.2%) did not. One hundred and sixty-three neurologists (56%) reported increased side effects in their patients after a switch from a brand name to generic AED; 128 (44%) did not. Fifty-two (18.4%) neurologists agreed that the Food and Drug Administration standards for AED bioavailability are sufficiently narrow; 231 (81.6%) did not.