Frequency of Subclinic Hypothyroidism at the Patients That Are Using Valproic Acid

Valproic acid is one of the most commonly used anti-epileptics in the treatment of childhood epilepsy. The aim of this study was to determine the risk factors for and incidence of subclinical hypothyroidism (SH) in children with idiopathic epilepsy using valproic acid (VPA). Patients monitored with a diagnosis of idiopathic epilepsy, using valproic acid for longer than 12 months and who were seizure-free for at least 6 months were included in the study. Levels of free thyroxine, free triiodothyronine and thyrotropin were measured. The results were then compared with those of the control group. Rates of SH in patients using VPA and the control group were 18.5% and 6.2%, respectively. The difference was statistically significant (P<0.01). SH was not correlated with age or dose of drug used (P>0.01). In conclusion, SH is a common effect seen in children with epilepsy using VPA. It will be beneficial to measure thyroid functions at specific intervals.