The effect of antiepileptic drugs on thyroid hormonal function: valproic acid and phenobarbital

Area of Science:

• Pediatric Endocrinology
• Neurology
• Pharmacology

Background:

• Epilepsy is a common neurological disorder in children.
• Antiepileptic drugs (AEDs) are the cornerstone of epilepsy management.
• Potential side effects of AEDs on endocrine function, including thyroid function, require investigation.

Purpose of the Study:

• To assess thyroid function alterations in pediatric epilepsy patients undergoing treatment with valproic acid or phenobarbital.
• To compare thyroid hormone levels before and after 12 months of AED therapy.
• To determine the incidence of subclinical hypothyroidism in children treated with specific AEDs.

Main Methods:

• A cohort of 183 pediatric epilepsy patients (aged 15 months-16 years) was studied.
• Patients were treated with either valproic acid (n=114) or phenobarbital (n=69).
• Thyroid-stimulating hormone (TSH) and free triiodothyronine (fT3) levels were measured pre-treatment and at 12 months, compared to 151 age-matched healthy controls.

Main Results:

• TSH levels were significantly elevated at 12 months in both valproic acid and phenobarbital groups.
• Pre-treatment fT3 levels were higher in epileptic patients compared to controls.
• Subclinical hypothyroidism was observed in 15.2% of the valproic acid group and 2.9% of the phenobarbital group at 12 months, with a significant increase from baseline in the valproic acid group.

Conclusions:

• Long-term use of valproic acid and phenobarbital in children with epilepsy is associated with thyroid function alterations.
• Regular monitoring of thyroid function is crucial for pediatric patients on long-term valproic acid or phenobarbital therapy.
• The findings highlight the need for vigilant assessment of thyroid health in children with epilepsy receiving AEDs.