SHORT COMMUNICATION Comparison of carbamazepine and oxcarbazepine effects on aminothiol levels Stéphanie Badiou & Hélène Breton & Hélène Peyriere & Virginie Charasson & Arielle Crespel & Philippe Gelisse & Jean-Paul Cristol & Dominique Hillaire-Buys Received: 27 June 2007 / Accepted: 20 September 2007 / Published online: 31 October 2007 # Springer-Verlag 2007 Abstract Objective The aim of our study was to investigate the effects of carbamazepine (CBZ) and oxcarbazepine (OXCBZ) on aminothiol levels, including homocysteine (Hcy), cysteine, and cysteinylglycine, in chronically treated patients. Methods Epileptic patients receiving CBZ or OXCBZ were recruited as part of routine clinical practice. Demographic data and concomitant medications were recorded from the patient medical file. Results Sixty patients were included in the study; 30 patients were treated with CBZ and 30 with OXCBZ. Median Hcy level was significantly higher in CBZ-treated patients (20.6 μmol/l) than in OXCBZ-treated patients (14.0 μmol/l, p <0.0001). No correlation was evidenced between antiepileptic drugs or metabolite levels and Hcy levels for each group. Conclusions Less change observed with OXCBZ compared with CBZ on aminothiol levels could constitute an advantage for OXCBZ treatment in patients with other factors influencing Hcy levels and/or at high risk for cardiovascular diseases. Keywords Carbamazepine . Oxcarbazepine . Aminothiols . Homocysteine Introduction Plasma homocysteine (Hcy) level was constantly increased in patients treated for epilepsy compared with healthy controls, mainly due to altered remethylation of Hcy in methionine. However, discrepant results were obtained when assessing the effect of each available antiepileptic drug (AED) on remethylation cofactors folate or vitamin B12 levels [1–5]. Recently, the comparison of treated and untreated epileptic patients highlighted the role of AEDs per se in increased Hcy levels [6]. Considering the long- term use of AED therapy and the role of Hcy in endothelial dysfunction, a key event in atherosclerosis, hyperhomocys- teinemia should be a clinical concern for cardiovascular risk management in epileptic patients [7, 8]. Among available anticonvulsants, carbamazepine (CBZ) is one of the most effective. More recently, oxcarbazepine (OXCBZ), a chem- ically CBZ-related drug, was marketed. This drug differs from CBZ by an additive carbonyl function and is claimed to be a less enzymatic inducer [9]. No study has been carried out to compare the effect of CBZ and OXCBZ on aminothiol levels. In this work, we assessed the respective effect of CBZ and OXCBZ on Hcy, cysteine, and cysteinylglycine status and evaluated the potential relation- ship between plasma AEDs or metabolite concentrations and Hcy levels in chronically treated epileptic patients. Eur J Clin Pharmacol (2008) 64:83–87 DOI 10.1007/s00228-007-0388-z DO00388; No of Pages S. Badiou : J.-P. Cristol Laboratoire de Biochimie, Hôpital Lapeyronie, Montpellier Cedex 5, France H. Breton : H. Peyriere (*) : V. Charasson : D. Hillaire-Buys Service de Pharmacologie Médicale et Toxicologie, Hôpital Lapeyronie, 371 avenue du Doyen Gaston Giraud, 34295 Montpellier Cedex 5, France e-mail: h-peyriere@chu-montpellier.fr A. Crespel : P. Gelisse Service de Neurologie, Hôpital Gui de Chauliac, CHU de Montpellier, Université Montpellier I, Montpellier Cedex 5, France