[The influence on the thyroid hormone system by long-term anticonvulsive therapy with valproat (author's transl)].

Valproat lowers the serum concentraiton of PBI and T4 in epileptic children. Since this reduction is not so pronounced with PBI as with T4, the difference in comparison with the controls could not be statistically verified with the desired probability of error. The reduction of general thyroxine can be statistically verified when compared with healthy control individuals. Free thyroxine is not influenced by Valproat therapy. The TBG TSH and the T3 in vitro test do not indicate variations from the healthy control subjects. The same is true for serum cholesterol. Valproat does not cause hypothyroidism; the reduction in PBI values and T4 serum concentration must be explained by competative displacement out of the protein bonds by Valproat.