Thyroid hormones in children with epilepsy during long-term administration of carbamazepine and valproate
Alberto Verrotti1, Melissa Laus, Alessandra Scardapane
1Department of Pediatrics, University of Chieti, Chieti, Italy. averrott@unich.it
Insights
Valproate acid (VPA) monotherapy does not affect thyroid hormones in epileptic children. Carbamazepine (CBZ) therapy, however, leads to alterations in thyroid hormone levels, though patients remain euthyroid.
Area of Science:
- Pediatric Endocrinology
- Clinical Neurology
- Pharmacology
Background:
- Epilepsy is a common neurological disorder in children.
- Long-term antiepileptic drug (AED) therapy can impact various physiological systems.
- Thyroid function is crucial for overall health and development in pediatric populations.
Purpose of the Study:
- To investigate the long-term effects of carbamazepine (CBZ) and valproate acid (VPA) monotherapy on thyroid function in children with epilepsy.
- To compare thyroid hormone levels and thyroid autoantibodies in children treated with CBZ versus VPA against a control group.
Main Methods:
- A prospective study involving 32 newly diagnosed pediatric epilepsy patients (18 on CBZ, 14 on VPA) and 32 age- and sex-matched controls.
- Evaluation of serum thyroid-stimulating hormone (TSH), thyroxine (T4), triiodothyronine (T3), free thyroxine (fT4), free triiodothyronine (fT3), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Ab) at baseline and 3, 6, and 12 months.
- Performance of thyrotropin-releasing hormone (TRH) stimulation tests at all evaluation points for patients and at baseline for controls.
Main Results:
- CBZ treatment was associated with significantly lower serum T4 and fT4 levels at 3, 6, and 12 months compared to baseline and controls.
- VPA monotherapy did not significantly alter serum T4, fT4, T3, or fT3 levels throughout the study.
- All patients maintained normal T3, fT3, and TRH test responses, and TPO-Ab and TG-Ab were absent, indicating euthyroid status despite CBZ-induced hormone alterations.
Conclusions:
- VPA monotherapy appears safe concerning thyroid function in pediatric epilepsy patients.
- CBZ therapy can induce significant alterations in thyroid hormone levels (T4 and fT4) in children with epilepsy.
- Despite observed thyroid hormone changes with CBZ, clinical or subclinical hypothyroidism was not detected in the study cohort.
Objective:
This study evaluates the effects of long-term carbamazepine (CBZ) and valproate acid (VPA) therapy on thyroid function in epileptic children.
Design:
A prospective study performed in 32 newly diagnosed pediatric patients, subdivided into two groups: 18 patients treated with CBZ and 14 patients treated with VPA. Thirty-two sex- and age- matched subjects served as controls.
Methods:
Serum TSH, thyroxine (T(4)), triiodothyronine (T(3)), free thyroxine (fT(4)), free triiodothyronine (fT(3)), thyroid peroxidase antibodies (TPO-Ab), and thyroglobulin antibodies (TG-Ab) were evaluated at baseline and at the 3rd, 6th, and 12th month in all patients and in the control group. A TRH stimulation test was performed in all epileptic patients at baseline and at the 3rd, 6th, and 12th month evaluations while in controls only baseline assessment was carried out.
Results:
At baseline evaluation, thyroid function was normal in all epileptic children. After 3 months, CBZ-treated patients showed serum T(4) and fT(4) levels significantly lower than baseline evaluation and control subjects. Serum T(4) and fT(4) concentrations were unaffected by VPA monotherapy. Serum T(3) and fT(3) were normal in both CBZ-treated and VPA-treated patients. TRH test was normal in all patients. At 6th and 12th month evaluations, the same alterations were present in CBZ-treated patients while thyroid function remained normal in VPA-treated patients. TRH test responses were normal in all epileptic patients. TPO-Ab and TG-Ab were always absent in all patients.
Conclusions:
Our data suggest that VPA monotherapy does not alter thyroid hormones. On the contrary, alterations of thyroid hormones occur in CBZ-treated children. However, the patients are euthyroid and thyroid hormone alterations are not associated with clinical or subclinical hypothyroidism.
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