An Examination of the Effects of Phenobarbital on Thyroid Function Tests in Childhood Epilepsy

Aim: The aim of this study was to evaluate changes in thyroid function tests in a group of epileptic children taking phenobarbital. Materials and Methods: Patients' demographic data and free thyroxine (FT4), free triiodothyronine (FT3) and thyroid-stimulating hormone (TSH) levels during at least 12 months of treatment were recorded. Forty-eight children using phenobarbital and 45 healthy children were enrolled. Results: In the phenobarbital group, FT3 level was 4.14±0.1 pg/mL, FT4 1.22±0.01 ng/dL and TSH 2.88±0.21 mIU/L. In the control group, FT3 level was 4.28±0.08 pg/mL, FT4 1.34±0.02 ng/dL and TSH 2.28±0.19 mIU/L. The rates of subclinical hypothyroidism between the two groups were not show statistically significant difference (p=0.16). Conclusion: The use of phenobarbital in the treatment of childhood epilepsy does not appear to increase the risk of thyroid dysfunction.