The study power would certainly have been maximal for a trial comparing therapeutic drug monitoring-based dosage individualization to a complete abstention from TDM. However, according to our experience, the mere existence of analytical services makes it difficult to deny access to certain patients on the argument that they belong to a control group, raising ethical concerns in case of perceived need for measurement in potentially worrying clinical conditions. Therefore, this study adopts a pragmatic approach, aiming to compare a routine a priori adjustment of newer generation antiepileptic drugs dosage based on therapeutic drug monitoring with a selective a posteriori offer for therapeutic drug monitoring services in case of clinical problems (such as insufficient response, or suspicion of medication toxicity). It is conceivable that such a design could lower the risk of bias favouring therapeutic drug monitoring, as prescribers willing to obtain measurement results in patients from the control group may be subtly incited to notify more easily the occurrence of clinical problems in this group. The endpoint will be however well defined to minimise this potential bias.