Thyroid Hormone Levels in Children Receiving Carbamazepine or Valproate

Pediatric Neurology , 08/12/2011

The authors conclude that carbamazepine and valproate therapy alters thyroid functions by decreasing free thyroxine levels. Compensation by increase in thyroid–stimulating hormone is better with valproate.

Methods

  • Free triiodothyronine, free thyroxine, and thyroid-stimulating hormone were measured by electrochemiluminescent assay in 30 children receiving carbamazepine, 34 children receiving valproate, and 30 age- and sex-matched control subjects.
  • Groups were similar for age, body mass index, and duration of therapy.
  • Thyroid-stimulating hormone (mean ± S.D.) was 2.67 ± 1.66, 4.53 ± 1.9, and 3.61 ± 1.75 μIU/mL in the control, valproate, and carbamazepine group, respectively (P < 0.001).

Results

  • Thyroid-stimulating hormone (mean ± S.D.) was 2.67 ± 1.66, 4.53 ± 1.9, and 3.61 ± 1.75 μIU/mL in the control, valproate, and carbamazepine group, respectively (P < 0.001).
  • Free thyroxine was 1.39 ± 0.19, 1.40 ± 0.63, 1.11 ± 0.19 ng/dL (P = 0.009). Free triiodothyronine was 4.03 ± 0.74, 4.14 ± 0.94, 3.92 ± 0.68 pg/mL (P = 0.54). When groups were compared 2 at a time, there was no difference in free triiodothyronine (P > 0.05).
  • Free thyroxine levels in the carbamazepine group were significantly different from valproate (P = 0.015) and control (P = 0.027).
  • Thyroid-stimulating hormone increased with both valproate and carbamazepine compared to control but was significant with valproate (P < 0.001).

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