Effect of levetiracetam on testosterone levels in male patients

We sought to determine whether the testosterone increase found with levetiracetam exposure in animal studies also occurs in patients. Adult male patients were evaluated for reproductive hormone levels before and 1 month after levetiracetam therapy. Eight subjects met inclusion/exclusion criteria (mean age 46 years, range 29-75 years). Total testosterone prior to starting levetiracetam ranged from 206-787 ng/dl [mean 445, standard deviation (SD) 227]. The mean total testosterone after levetiracetam therapy increased to 592 ng/dl (range 216-981, SD 297), an increase of 16% (p = 0.036). The free testosterone increased from a mean of 64 pg/ml (range 36-115, SD 30) to a mean of 76 pg/ml (range 35-155, SD 44), an increase of 19% (p = 0.080). The magnitude of change in testosterone levels correlated with the initial testosterone level (p = 0.038, r = 0.734). These results suggest that levetiracetam increases testosterone levels and that an initial testosterone level may predict the magnitude of increase.