Effect of Antiepileptic Drug Treatment on Thyroid Hormone Levels in Epilepsy Patients

Aim:Antiepileptic drugs (AEDs) can have an effect on hormone metabolism and function, and alter serum levels of some hormones. This study aimed to determine the effects of AEDs on thyroid function test results in epilepsy patients.Methods:The study included 82 epilepsy patients aged 18-45 years. Serum free thyroxin (fT4), free triiodothyronine (fT3), and thyroid-stimulating hormone (TSH) levels were measured in all the participants. Thyroid hormone levels in subgroups were investigated. In addition, Serum AED and thyroid hormone levels and duration of AED use and thyroid hormone levels were analyzed.Results:Although there were differences in thyroid hormone levels among patient subgroups, the differences did not reach statistical significance. There was no significant correlation between the duration of AED use and thyroid function parameters in the monotherapy subgroup. The only correlation observed between serum AED levels and thyroid function test results was that decreased serum fT4 level was associated with decreased carbamazepine level in blood.Conclusion:In this study, we found a significant decrease in fT4 level with only increased serum carbamazepine level. Different results in our study and similar studies in the literature showed that there could be many different physiological and environmental factors affecting thyroid hormone levels