Thyroid functions as a parameter in monitoring of antiepileptic drugs

ABSTRACT

Introduction

Epilepsy is a chronic neurological disorder that is treated with multiple medications that can have significant side effects. This study investigated the potential effects of antiepileptic drugs on thyroid function.

Methods

The participants in this study were epileptic adults who had been consistently monitored in follow-up care. The effects of antiepileptic drugs on the serum levels of the thyroid stimulating hormone (TSH), free T3 (fT3), and free T4 (fT4) of these patients were investigated retrospectively by comparing laboratory recordings in three defined periods: prior to antiepileptic drug treatment, between 6 months and 1 year of treatment (early stage), and after 1 year of treatment (late stage).

Results

  A total of 300 epileptic patients (F/M: 175/125) were included in the study. Significant differences in TSH and fT4 serum levels in the late stage compared to the pre-treatment stage (p = 0.006 and p = 0.0005, respectively) were found. TSH values in the late stage of treatment were abnormally high in one case and low in five cases; all six of these cases had normal pre-treatment and early-stage TSH values. Patients who received monotherapy with valproic acid, levetiracetam or carbamazepine were evaluated separately and there was no statistically significant difference in TSH and fT3 levels, while fT4 levels were significantly increased during treatment in each treatment group.

Conclusions

A significant increase in TSH levels was found in epileptic patients on polytherapy. Our results give us the opportunity to highlight the potential unique or cumulative effect of antiepileptic drugs on thyroid hormone levels.

KEYWORDS:

• Epilepsy
• antiepileptic drugs
• thyroid function

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

Ekim Comert

Ekim Comert, MD is neurologist. He received his specialty training at Zonguldak Bulent Ecevit University.

Ulufer Celebi

Ulufer Celebi, MD is assistant professor at Zonguldak Bulent Ecevit University, Turkey. She is physician with main interest in epilepsy. She continues assistant training and academic studies.

Bilge Piri Cinar

Bilge Piri Cinar, MD is associate professor at Zonguldak Bulent Ecevit University, Turkey. She is physician with main interest in multiple sclerosis and cognition. She is board member of Multiple Sclerosis Research Association.

Mustafa Acikgoz

Mustafa Acikgoz, MD is assistant professor at Zonguldak Bulent Ecevit University, Turkey. He is physician with main interest in multiple sclerosis and neuromuscular junction disorders.

Esra Aciman Demirel

Esra Aciman Demirel, MD is assistant professor at Zonguldak Bulent Ecevit University, Turkey. She is physician with main interest in headache, movement disorders and behavioral neurology.

Huseyin Tugrul Atasoy

Huseyin Tugrul Atasoy, MD is Professor of Neurology at Zonguldak Bulent Ecevit University, Turkey. He is physician with main interest in headache, behavioral neurology and neurophysiology.