Randomised controlled monotherapy trials: which comparators to use?

As approximately 50% of patients with newly diagnosed epilepsy achieve seizure remission after initial monotherapy, the selection of the first-choice drug to be used as the gold standard in randomised clinical trials is critical. Several first and second generation drugs have been used in regulatory and pragmatic monotherapy trials with similar efficacy but differing pharmacokinetic, tolerability, and safety profiles. None of the available compounds has an ideal profile and second generation drugs do not appear to present unequivocal advantages in this regard. Compared to first generation drugs, some newer generation antiepileptic drugs may be preferred as they have similar efficacy but lower potential for idiosyncratic reactions and drug interactions. However, more recent antiepileptic drugs also have limitations, which include lack of superiority and, in some cases, unbearable adverse effects. In this light, there are no standard criteria as a reference for the selection of the best comparator for new monotherapy trials. However, according to the recommendations of evidence-based guidelines, carbamazepine still represents the first-choice drug for patients with partial epilepsy. Ethosuximide may be an option for absence epilepsy. In contrast, for the treatment of patients with other generalised epilepsies, there is no clear indication of preferred drug, as valproate, which has been found to prevail over other compounds, should be withheld in women of childbearing age due to its teratogenic potential, and there is insufficient evidence to choose an alternative drug.