Park Hyunju, Heo Jung, Kim Min-Ji, Lee Jee-Hun, Kim Min-Sun, Jin Dong-Kyu, Kim Tae Hyuk, Chung Jae Hoon, Cho Sung Yoon, Kim Sun Wook
Division of Endocrinology and Metabolism, Department of Medicine, Thyroid Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Statistics and Data Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul, Korea.
Epilepsia. 2022 Dec;63(12):3148-3155. doi: 10.1111/epi.17407. Epub 2022 Oct 1.
Thyroid hormone abnormalities have been linked to antiseizure medications (ASMs). Oxcarbazepine is considered safer than carbamazepine because it induces the hepatic cytochrome P450 metabolic enzymes less than the carbamazepine does. However, limited data exist for the influence of oxcarbazepine on thyroid function in children and adolescents. The objective of this study was to determine the effect of oxcarbazepine on thyroid function in these patients.
A total of 162 pediatric patients with epilepsy who started oxcarbazepine for the first time between April 2003 and May 2020 were enrolled. The longitudinal effects of oxcarbazepine for thyroid functions were confirmed using general estimating equations.
Serum triiodothyronine (T3), thyroxine (T4), and free thyroxine (fT4) levels decreased significantly during 5 years of follow-up (all p's < .001). In particular, T3 and fT4 levels were reduced steeply in the first 2 years of oxcarbazepine treatment. There was no significant change in thyroid-stimulating hormone during oxcarbazepine treatment.
Serum T3, T4, and fT4 levels decreased significantly during oxcarbazepine use, and this change was maintained during the treatment period. In patients receiving oxcarbazepine, it is recommended that periodic thyroid function testing should be performed, especially within the first 2 years after starting this ASM. Our results indicate that oxcarbazepine-induced hypothyroidism does not appear to be accompanied by a significant increase in TSH, and consequently might be missed if TSH alone is monitored as a measure of thyroid dysfunction.
