Abrupt switch from extended-release oxcarbazepine to eslicarbazepine acetate

Background. Eslicarbazepine acetate (ESL) was labelled for add-on treatment of adults with focal epilepsies in 2009. ESL is a derivative of carbamazepine and oxcarbazepine (OXC) that promises potentially better effectiveness. It has not yet been investigated how to switch from OXC to ESL and if this switch causes any clinical changes. Material and methods. We replaced extended-release OXC by ESL abruptly according to a 1:1 ratio in 12 patients. Standardized tests and questionnaires addressing side effects, quality of life and alertness were performed immediately prior and 5 days after the switch. We also measured the serum levels of sodium and the common metabolite monohydroxy derivative. Results. No problems occurred. Concerning the parameters investigated no significant differences were found. In 9 of 12 cases serum sodium levels fell without clinical consequences. Conclusion. The exchange of extended-release OXC by ESL is easy to perform. Clinically relevant alterations were not apparent immediately after the switch. Sodium serum level controls are recommended also with the use of ESL