Background: Antiepileptic(AED) drugs are an integral component of management of seizure disorder, however they have wide spectrum of adverse effects. It is important to be aware of these side effects as they have a major impact on quality of life and are sometimes partially reversible after drug discontinuation. Among them the influence of AED on thyroid function is an important one. But there is only limited data available. Objective of this study is to evaluate the effect of AED on Thyroid Stimulating Hormone(TSH)

Methodology: A cross-sectional study of one-year duration (march 2017 – march 2018) was conducted among 150 epileptic patients receiving Phenytoin, Carbamazepine, Sodium valproate for more than six months in a tertiary care center in central Kerala. Serum levels of TSH of patients on AED were compared with that of 50 healthy age and sex matched control group. Data regarding the same were analyzed using SPSS version 16 with chi square test , ANOA and independent t test.
Results: A total of 150 epileptic patients with mean age of 35.54 + 10.72, including 66 males (44%) and 84 females (56%) were enrolled in this study. 50 adults of men age 36.5+ 8.4 and male to female ratio 1.10 :1 formed the control group. It was found that mean TSH value of patients on Phenytoin (3.97+ 1.47) , Carbamazepine (3.57+ 1.44) and Sodium valproate 3.03 + 1.41 significantly higher than that of control group (1.91 + 0.72). On comparing the mean serum TSH of drug group significant difference noted between Phenytoin and Sodium Valproate treated group. Among the 12 patients develop subclinical hypothyroidism 65% taking drugs for more than five years.
Conclusion: There is a positive correlation between use of anticonvulsants and thyroid dysfunction and the association increases with duration of therapy. The clinicians should be encouraged for regular monitoring of thyroid function test. So as to impart better quality of life to the patients.