Thyroid hormones in epileptic children receiving carbamazepine and valproic acid

Carbamazepine and valproic acid are effective antiepileptic drugs for treat ing many types of epilepsy. Although they are well tolerated, many effects on endocrine function have been reported. Changes in serum thyroid hormones levels in 37 children with epilepsy during carbamazepine and valproic acid therapy were analyzed, and the thyroid hormone concentration after thyrotr opin-releasing hormone test was evaluated. Serum thyroxine and free thyroxi ne levels were significantly lower in patients treated with carbamazepine a nd carbamazepine plus valproic acid than in the control subjects; serum thy roxine and free thyroxine concentrations were unaffected by valproic acid m onotherapy. Serum triiodothyronine and free triiodothyronine concentrations were similar in the three groups of patients studied. Thyroid-stimulating hormone serum levels were normal in all patients, and the thyrotropin respo nses to the thyrotropin-releasing hormone were similar to control group. Ou r data suggest that children treated with carbamazepine may have subclinica l signs of hypothyroidism, and these changes are more evident if carbamazep ine is given in association with valproic acid, while no alteration in thyr oid hormones can be found with valproic acid monotherapy. Thyroid-stimulati ng hormone and thyrotropin-releasing hormone levels do not seem to be affec ted by these drugs, suggesting that hypothalamic function is not affected i n these children. (C) 2001 by Elsevier Science Inc. All rights reserved.