POSITION STATEMENT ON THE COVERAGE OF ANTICONVULSANT DRUGS FOR THE TREATMENT OF EPILEPSY

Abstract

We read with concern the position statement1 and editorial2 on generic substitution of antiepileptic drugs (AEDs). The American Epilepsy Society and the Epilepsy Foundation are also studying generic substitution and legislation restricting generic prescription is being considered throughout the United States. These efforts are surprising since there is scant published evidence of problems with current generic AED formulations, and generic versions of many newer AEDs have yet to be released. While problems have been noted with older generic formulations of poorly water-soluble AEDs such as phenytoin, generic versions of newer, highly soluble AEDs such as gabapentin, zonisamide, lamotrigine, topiramate, and levetiracetam are unlikely to have similar problems.3 Nonetheless, hard evidence is absent. We feel that prospective, blinded, randomized trials—not anecdotal opinion surveys—are required to address a highly concrete, quantifiable subject: whether generic AEDs achieve significantly different serum levels than brand versions. Despite the paucity of data, legislation has been proposed in Washington State (HB 2123)4 among others, which would impede prescription of generic AEDs by requiring providers and patients to separately consent to their dispensing. This will diminish the use of generics by allowing patients to opt out of generic substitution when the prescription is filled, and by confronting providers with additional paperwork. These barriers to generic competition will only increase prescription drug costs, both for the patient who pays out of pocket and for third-party and government health care payers. This is not in the patient’s best interest. We also need to acknowledge the significant financial forces that may influence the debate. Brand name AEDs each generate hundreds of millions of dollars annually in revenue for the manufacturer, and this revenue typically drops by 80 to 90% in the first year after generic versions are introduced. Thus, the pharmaceutical industry has a vested interest in …