Effects of Carbamazepine on the Hypothalamic-Pituitary-Gonadal Axis in Male Patients with Epilepsy: A Prospective Study

The effects of carbamazepine (CBZ) monotherapy on serum sex hormone levels and on pituitary responsiveness to various stimuli were evaluated in a prospective study with 21 male patients with epilepsy. The serum levels of testosterone (T), free testosterone (FT), sex hormone binding globulin (SHBG), estradiol (E2), luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), and dehydroepiandrosterone sulfate (DHEAS) were assayed, and the free androgen index (FAI) values were calculated for each patient before and after 2-month CBZ treatment. The pituitary PRL, LH, and FSH responses to luteinizing hormone-releasing hormone (LH-RH), thyrotropin-releasing hormone (TRH), and metoclopramide (MC) were also measured before and after CBZ treatment. The baseline serum hormone and SHBG levels were measured and the FAI values calculated in 16 healthy male control subjects of similar age. The mean E2 level was higher in patients before CBZ treatment than in control subjects, and untreated patients had greater variances for FAI values, PRL levels, and LH levels than control subjects. No other significant differences were found between untreated patients and control subjects. The FAI values and DHEAS levels of patients decreased during 2-month treatment with CBZ. The PRL response to MC was higher after CBZ treatment than before. The baseline levels of other hormones and SHBG, as well as the LH and FSH responses to LH-RH, remained unaltered. The results indicate that during the first 2 months of CBZ treatment the androgen balance in male epileptic patients changes: Serum DHEAS levels and FAI values decrease, although FT levels remain unchanged. The clinical relevance of these hormonal changes is obscure.