The evaluation of thyroid functions, thyroid antibodies, and thyroid volumes in children with epilepsy during short-term administration of oxcarbazepine and valproate.
OBJECTIVE
The aim of this study was to evaluate the effects of short-term oxcarbazepine (OXC) and valproate (VPA) monotherapy on thyroid functions in children.


METHODS
Fifty-five newly diagnosed epileptic children with normal thyroid functions (confirmed with the thyrotropin releasing hormone stimulation test) participated in this study. VPA treatment was started in 30 patients and OXC in 25 patients. Serum thyroxine (T(4)), free thyroxine (fT(4)), triiodothyronine (T(3)), free triiodothyronine (fT(3)), reverse T3 (rT(3)), thyroid peroxidase antibodies (TPO-ab), and urine iodine levels were evaluated at baseline and at the third and sixth months of therapy.


RESULTS
In the OXC group, serum T(4), fT(4), T(3), fT(3), and rT(3) levels were found to be decreased at the third and sixth months, the differences were significant compared to the baseline values except for fT(3) levels at the third month and fT(4) and rT(3) levels at the sixth month (p < 0.05). At the sixth month, serum T(4) level dropped below the normal reference value in 8 (32%), fT(4) in 5 (20%), T(3) in 4 (16%), and fT(3) in 3 (12%) patients. In the VPA group, mean T(4), fT(4), T(3), fT(3), and rT(3) levels at 3 and 6 months remained similar compared to the baseline values (p > 0.05). Mean serum thyroid stimulating hormone levels increased significantly at the sixth month compared to the baseline values in the VPA group (p < 0.05) while it remained unchanged in the OXC group (p > 0.05). There was no effect of either drug on urinary iodine excretion and serum TPO-ab levels remained in normal ranges throughout the study.


CONCLUSIONS
In this prospective study, it is documented that children under short-term OXC or VPA therapy showed altered thyroid functions similar to the changes observed after long-term treatment. Although, the clinical significance of these results need to be evaluated with future studies, this observation of altered thyroid functions points out that thyroid functions may need to be monitored closely in children receiving antiepileptic treatment, even in the short-time interval.
Cansu
Ali
A
Department of Pediatric Neurology, Gazi University Faculty of Medcine, Ankara, Turkey. acansu2003@yahoo.com
Serdaroğlu
Ayşe
A
Camurdan
Orhun
O
Hirfanoğlu
Tuğba
T
Bideci
Aysun
A
Gücüyener
Kivilcim
K
D000906:Antibodies / Q000032:analysis / Q000276:immunology; D000927:Anticonvulsants / Q000494:pharmacology / Q000627:therapeutic use*; D002220:Carbamazepine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D002648:Child; D004334:Drug Administration Schedule; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy* / Q000276:immunology; D006801:Humans; D007453:Iodide Peroxidase / Q000276:immunology; D007455:Iodine / Q000652:urine; D008137:Longitudinal Studies; D000078330:Oxcarbazepine; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000033:anatomy & histology* / Q000276:immunology*; D013963:Thyroid Hormones / Q000097:blood; D013997:Time Factors; D014635:Valproic Acid / Q000494:pharmacology / Q000627:therapeutic use*
D000906:Antibodies; D000927:Anticonvulsants; D013963:Thyroid Hormones; D002220:Carbamazepine; D014635:Valproic Acid; D007455:Iodine; D007453:Iodide Peroxidase; D000078330:Oxcarbazepine