Oxcarbazepine and Carbamazepine: Expected and Unexpected Differences and Similarities

Lofgren E, Tapanainen JS, Koivunen R, Pakarinen A, Isojarvi JI. Epilepsia 2006;47(9):1441–1446. PURPOSE: The aim of the study was to compare the effects of carbamazepine (CBZ) and oxcarbazepine (OXC) on the reproductive endocrine function in women with epilepsy. OXC is a novel antiepileptic drug (AED), and the occurrence of reproductive dysfunction in women treated with OXC monotherapy for epilepsy has not been studied previously. METHODS: Thirty‐five women with epilepsy were examined in the Department of Neurology at Oulu University Hospital. Sixteen patients were treated with CBZ monotherapy, and nineteen patients were treated with OXC monotherapy. The subjects were clinically examined, vaginal ultrasonography was performed, and serum sex hormone concentrations were measured. RESULTS: The women taking CBZ or OXC had lower serum testosterone (T) levels and lower free androgen indexes (FAIs) than the control subjects. CBZ medication was associated with increased concentrations of serum sex hormone–binding globulin (SHBG). The patients taking OXC had higher concentrations of dehydroepiandrosterone sulfate (DHEAS) and androstendione (A) than did the women taking CBZ. Moreover, the prevalence of polycystic ovaries (PCOs) was high in the OXC‐treated women. CONCLUSIONS: CBZ and OXC have different effects on the reproductive endocrine function. Although both drugs were associated with low serum T concentrations and low FAIs, only OXC was associated with a high frequency of elevated levels of A and DHEAS and with an increased prevalence of PCOs. These findings suggest that OXC may be disadvantageous for women with epilepsy and hyperandrogenism, whereas CBZ may be beneficial for these women.