The drugs are not all the same

Editor-A G Marson and colleagues' systematic review of new antiepileptic drugs is unhelpful for two reasons.1 “Regulatory” placebo controlled trials are not suitable evidence for a comparison of new antiepileptic drugs, and, perhaps more importantly, the authors give the erroneous impression that all new antiepileptic drugs are interchangeable.

It is hardly surprising that the main positive conclusion of this review is that each of the new antiepileptic drugs has proved more effective than placebo, because most of the studies were designed to show just that.2 In addition, the trials looked at different subsets of patients who had previously been exposed to different antiepileptic drugs; the patients were receiving different relative doses of different (and sometimes interacting) antiepileptic drugs, and often the titration schedules that were used were different from those that were later recommended. For each compound the trials showed superiority over placebo with acceptable tolerability, and the outcome of this exercise was that a product licence was granted for each compound. Comparison among antiepileptic drugs across such a wide range of varied studies is not a proper basis for an evidence based approach to the management of refractory partial epilepsy.

A second point is that this is not a horse race, which implies a fair contest among members of the same species. These new antiepileptic drugs have different, sometimes overlapping, and often multiple mechanisms of …