We have previously performed long-term studies of rats treated with levetiracetam and compared them with a control group. Here we have found that levetiracetam has a probable effect on the ovaries, since the treated animals had larger ovaries, fewer cysts, more corporea lutea and more secondary follicles than the untreated animals (Taubøll et al 2004). Blood tests on the animals showed that those treated with levetiracetam had higher testosterone levels and lower levels of estrogen and FSH, whilst LH and progesterone levels were unaffected by the treatment (Svalheim et al, 2005a, b).

Studies on cell cultures from pig ovaries, as carried out by our group in collaboration with Jagiellonian University, Krakow, Poland, appeared to support these findings (Taubøll et al. 2006, submitted). Our wish therefore now is to study fertile men and women in order to look for any changes in the balance of sex hormones during use of levetiracetam in order to establish whether the findings in animal trials are clinically relevant to humans.