Thyroid hormones in children with epilepsy during long-term administration of carbamazepine and valproate

Objective: This study evaluates the effects of long-term carbamazepine (CBZ) and valproate acid (VPA) therapy on thyroid function in epileptic children. Design: A prospective Study performed in 32 newly diagnosed pediatric patients, subdivided into two groups: 18 patients treated with CBZ and 14 patients treated with VPA. Thirty-two sex- and age-matched subjects served as controls. Methods: Serum TSH, thyroxine (T-4), trilodothyronine (T-3), free thyroxine (fT(4)), free triiodothyronine (fT(3)), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Ab) were evaluated at baseline and at the 3rd, 6th, and 12th month in all patients and in the control group. A TRH stimulation test was performed in all epileptic patients at baseline and at the 3rd, 6th, and 12th month evaluations while in controls only baseline assessment was carried out. Results: At baseline evaluation, thyroid function was normal in all epileptic children. After 3 months, CBZ-treated patients showed serum T-4 and fT(4) levels significantly lower than baseline evaluation and control Subjects. Serum T-4 and fT(4) concentrations were unaffected by VPA nionotherapy. Serum T-3 and fT(3) were normal in both CBZ-treated and VPA-treated patients. TRH test was normal in all patients. At Ah and 12th month evaluations, the same alterations were present in CBZ-treated patients while thyroid function remained normal in VPA-treated patients. TRH test responses were normal in all epileptic patients. TPO-Ab and TG-Ab were always absent in all patients. Conclusions: Our data suggest that VPA nionotherapy does not alter thyroid hormones, On the contrary, alterations of thyroid hormones occur in CBZ-treated children. However, the patients are euthyroid and thyroid hormone alterations are not associated with clinical or subclinical hypothyroidism.