Significant Association of Antiepileptic Drug Polytherapy with Decreased FT4 Levels in Epileptic Patients.

Epileptic patients have to continue anti-epileptic drugs (AED) over a long period of time which can have deleterious effects on the endocrine system including the thyroid hormones with rare check. Risk factors for the development of thyroid dysfunction are still unclear. Therefore the aim of study was to evaluate thyroid functions in epileptic patients receiving anti-epileptic drugs (AED) as monotherapy and polytherapy and to determine potential risk of low thyroid function in epileptic patients receiving treatment. This cross-sectional study included 100 epilepsy patients more than 12 years of age. Serum levels of free thyroxin (FT4), free triiodothyronine (FT3), and thyroid stimulating hormone (TSH) were evaluated in all subjects in addition to serum AED levels. TSH levels were found to be significantly higher in the polytherapy subgroup (p < 0.05) in comparison to the monotherapy group. 44% of the patients in the VPA monotherapy group had raised TSH levels and 41.2% of the patients on CBZ had low FT4. A significant negative correlation was observed between CBZ and FT4 (p < 0.05). Female sex and old age were additional risk factors detected for deranged thyroid function. Female patients with epilepsy, an older age and AED polytherapy were found to be associated with a higher risk of thyroid dysfunction. Thus, Thyroid function in these patients should be monitored closely. In conclusion, we observed significant changes in thyroid hormone levels in patients receiving antiepileptic treatment in both monotherapy and polytherapy. Elevated CBZ levels were significantly associated with decreased FT4 levels. © Association of Clinical Biochemists of India 2021.