Generic substitution of anti-epileptic drugs. A needed battle?
ABSTRACT The clinical and economic consequences of generic antiepileptic drug (AED) substitution are not yet fully understood. Generic substitution may increase pharmacy utilization, but it may not always save health care costs for AEDs. The AEDs are relatively cheap, but high volumes of prescriptions mean that substantial drug-budget savings may be possible by switching from innovator brands to cheaper generic drugs. Such savings have been achieved in many other treatment areas. However, more caution may be needed for epilepsy because of the narrow therapeutic index, low solubility, and non-linear pharmacokinetics of some AEDs. This means that the ranges of bioequivalence that are authorized for generic formulations do not offer the same results regarding effectiveness and safety as those obtained by brand name drugs. This is why seizure control should not be sacrificed on the basis of cost alone, as the major endpoint in treating epilepsy with AEDs is seizure control without adverse effects. Switching to the cheapest generic AED may offer drug-budget savings that outweigh any risk to patient safety. But to date, this cost-benefit analysis has not been carried out. We propose that all changes to established principles of treating epilepsy are evidence based and that the risks of switching are clearly defined.