IMPE Abstracts

Introduction: Epilepsy is the most common neurological disorder that requires prolonged medication in children, with a prevalence of 0.5 to 1%. Carbamazepine is one of the most prescribed antiepileptic by neuropediatricians. The administration of carbamazepine is associated with decreased free thyroxine (FT4) levels being variable the relationship with thyrotropic hormone (TSH) values. When discontinuing therapy with carbamazepine, serum thyroid hormone levels normalize. Early diagnosis of hypothyroidism is important because thyroid hormones affect the normal development of the child, playing a crucial role in growth and puberty, bone growth, metabolism and body functions.

Objective: Determine thyroid function in epileptic children and adolescents medicated with carbamazepine.

Material and methods: Children and adolescents with epilepsy treated with carbamazepine, 10-20 mg/kg/day.

Variables: Age, sex and BMI of patients. At the beginning, after one month and six months of therapy with carbamazepine: Serum levels of FT4 and TSH. Reference levels: FT4, 0.8-1.9 ng/dL; TSH, 0.4-4.0 ulU/mL. Hormone levels exceeding these established ranges were considered pathological. Results: Investigated universe: 48 children with epilepsy, medicated with carbamazepine. Mean of age: 11.5 years (SD 1.9). Age range: 7-14 years. Sex: 30 (63%) male and 18 (37%) female Starting therapy: - Normal levels of FT4 and TSH: 44 patients (100.0%). Control - 1º month of treatment: - Normal levels of FT4 and TSH: 36 patients (82%). - Low FT4 levels and normal TSH concentrations: 7 (16%) - Low FT4 levels and high TSH concentrations: 1 (2%) Control - 6º month of treatment (n=43): - Normal levels of FT4 and TSH: 40 patients (93%). - Low FT4 levels and normal TSH concentrations: 3 (7%).

Conclusions: In some patients medicated with carbamazepine low FT4 levels were observed, with normal TSH concentrations. In rare cases, hypothyroidism was evident. The effect of carbamazepine on thyroid function was transient in some patients. Recommendation: Periodic monitoring of thyroid hormone levels recommended in patients treated with carbamazepine, to diagnose and treat early-stage hypothyroidism.