Effect of antiepileptic drug therapy on thyroid hormones among adult epileptic patients: An analytical cross-sectional study

OBJECTIVE: The objective of the study was to evaluate and compare the effect of conventional and newer antiepileptic drugs (AEDs) on thyroid hormone levels in adult epileptic patients. METHODS: A hospital-based, analytical cross-sectional study was conducted among the adult epileptic patients receiving conventional AEDs (Group 2) or newer AEDs (Group 3) for more than 6 months. Serum thyroid hormone levels including free triiodothyronine (fT(3)), free thyroxine (fT(4)), and thyroid stimulating hormone (TSH) were analyzed and the hormonal status was compared with healthy control subjects (Group 1). FINDINGS: Sodium valproate and phenytoin were commonly used conventional AEDs; levetiracetam and topiramate were common among the newer drugs. There was a statistically significant decrease in serum fT(4) and increase in serum TSH levels (P < 0.0001) in patients on long-term therapy with conventional antiepileptic agents than in the control group. No significant change in thyroid hormone levels (fT(3), fT(4), and TSH; P = 0.68, 0.37, and 0.90, respectively) was observed with newer antiepileptics-treated patients when compared to control group. One-way analysis of variance followed by post hoc Dunnett's test was performed using SPSS version 17.0 software package. CONCLUSION: The present study showed that conventional AEDs have significant alteration in the thyroid hormone levels than the newer antiepileptics in adult epileptic patients.