Carbamazepine and Its Metabolites in Epileptic Patients

This study was undertaken in an attempt to assess the role of the metabolites of carbamazepine, i.e. 10, 11-epoxy-carbamazepine and 10, 11-dihydro-10, 11-dihydroxy-carba-mazepine, with regard to their therapeutic efficacy and the occurrence of side effects of the parent drug. It was also designed to seek a possible explanation as to why certain patients with optimal levels of carbamazepine in plasma fail to respond to therapy. A total of 23 epileptic patients suffering from either generalized or partial complex seizures were chosen for this study. The results showed an association of high levels of metabolites with poor response to carbamazepine therapy. The non-response of carbamazepine in the patients with optimal level of carbamazepine plasma level may be due to competition by inactive dihydroxy metabolite to the site(s) action of the parent drug in the brain.