Testosterone-estradiol-binding globulin, unbound and total estradiol and testosterone, and total progesterone during the menstrual cycle in women with epilepsy taking antiepileptic drugs.

Total plasma estradiol, progesterone, testosterone, and the binding capacity of testosterone-estradiol-binding globulin (TeBG) were measured and plasma unbound estradiol and testosterone calculated, every second day during nine cycles in six patients with epilepsy. They all received phenytoin as one medication. Some had additionally, phenobarbital or ethosuximide. Plasma concentrations were compared with those of a group of healthy women without medication. Total plasma testosterone and TeBG binding capacity were significantly increased in the treated group, as compared to the control group. However, the unbound testosterone concentration was within the range of the controls. The percentage unbound testosterone of total plasma concentration was clearly below that of the control group. This indicates that there was a primarily increased TeBG binding capacity in patients taking antiepileptic drugs.