[Generic drugs in the treatment of epilepsy]

We discuss some controversial aspects with prescription of generic drugs (GD) and the problems concerning bioequivalence, mainly in the case of drugs with non-linear pharmacokinetics and/or narrow therapeutic rank, like the antiepileptic drugs (AED).

There is considerable debate about GD in the treatment of epilepsy, with clearly advantages (cost saving) and disadvantages (loss of seizure control or drug toxicity) in prescribing generics anticonvulsants. We make a systematic review of the literature in primary (PubMed) and secondary (Tripdatabase and Cochrane Library) bibliographic databases in relation to GD and AED. The main information is about classical AED (phenytoin, carbamazepine, valproic acid and primidone) and we don't found studies in this area about the new AED. The level of evidence is, generally, weak, based on case-series and expert opinion without explicit critical appraisal (except in phenytoin with level of evidence moderate, based on some analytical studies). In Spain, at this moment, there are only two generic AED, one-classical (carbamazepine) and one-new (gabapentin).

The American Academy of Neurology and Epilepsy Foundation maintains that the individual and physician should be notified and give their consent before a switch in antiepileptic medications is made, whether it involves generic substitution for brand name products, or generic to generic substitutions.