Perran BORAN, Yüksel YILMAZ, Serap TURAN, Abdullah BEREKET

Karbamazepin ve valproat monoterapilerinin tiroid fonksiyonu, lipid ve kemik metabolizması üzerine etkileri

Amaç: Valproat (VPA) ve karbamazepinin (CBZ), büyüyen gelişen çocuk organizmasında tiroid fonksiyonları, lipid ve kemik metabolizması üzerinde etkilerini araştırmak. Gereç ve Yöntem: Bu çalışmada en az 6 ay süre ile (22.2±14.1 ay) monoterapi olarak VPA (n: 47) ya da CBZ (n: 22) kullanmakta olan, mobilize, 69 epileptik çocukta (yaş: 9.8 ± 3.2 yıl), serum total triiyodotironin (T3), total tiroksin (T4), serbest tiroksin (sT4), tirotropik hormon (TSH), total kolesterol, trigliserid (TG), ağır yoğunluklu lipid (HDL), düşük yoğunluklu lipid (LDL), kalsiyum, fosfor, alkalen fosfataz (ALP) ve parathormon (PTH) düzeyleri araştırıldı ve sonografik olarak kemik yoğunluğu ölçümü yapıldı. Bulgular: CBZ kullanan 22 hastanın 9'unda (% 40.9) ve VPA alan 47 hastanın 6'sında (% 12.7) olmak üzere toplam 15 vakada (% 21.7) sT4 düzeylerinde düşüklük saptanırken, total T3, T4 ve TSH düzeylerinin etkilenmediği görüldü. CBZ alan 4 (% 18), VPA alan 6 (% 12.7) toplam 10 (% 14.5) hastada kan kolesterol düzeyleri 200 mg/dL'nin üzerinde bulundu, bu hastaların sekizinde LDL düzeyleri yüksekti. Kemik yoğunluğu tüm hastalarda normal bulunurken, vakaların % 18.8'inde sadece ALP yüksekliği, % 13'ünde sadece PTH yüksekliği, % 4'ünde ise ALP ve PTH yüksekliği saptandı. Sonuç: CBZ ve VPA kullanımının serum sT4 seviyelerinde CBZ kullanan vakalarda daha belirgin olarak düşüklüğe yol açtığı (p

Anahtar Kelimeler:

Epilepsi, Tiroid fonksiyon testleri, Tiroid hormonları, Lipid metabolizması, Valproik asit, Antikonvülzanlar, Karbamazepin

The effects of carbamazepine and valproic acid monotherapy on thyroid functions, lipid and bone metabolism

Aim: To determine the effects of valproic acid (VPA) and carbamazepine (CBZ) monotherapies on thyroid hormone functions, serum lipid levels and bone metabolism. Material and Methods: Sixty-nine ambulatory epileptic children (mean age: 9.8±3.2 years) who were receiving either VPA (n: 47) or CBZ (n: 22) for more than 6 months, were evaluated for serum total triidothyronine (T3), total thyroxine (T4), free thyroxine (fT4), thyrotropin (TSH), total cholesterol, triglycerides (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), calcium, phosphorus, alkaline phosphatase (ALP), and parathyroid hormone (PTH) levels. Bone mineral density measurements were done on all subjects by quantitative ultrasound. Results: Serum fT4 concentrations were below the normal range in 9 (40.9 %) of the CBZ receiving patients, and 6 (12.7 %) of the VPA receiving patients, with a total of 15 (21.7 %) cases in 69 patients. Serum total T3, total T4 and TSH levels were in the normal range in all patients studied. Total cholesterol levels were above the normal range in 4 (18 %) CBZ receiving patients, 6 (12.7 %) VPA receiving patients, total of 10 (14.5 %) in 69 patients. Serum LDL levels were elevated in eight of the 10 patients. No differences in bone mineral density were observed between patients and controls. Serum ALP levels were above the normal range in 18.8 %, PTH levels in 13 % and ALP and PTH levels in 4 % of the patients. Conclusion: Serum fT4 levels were lower in patients treated with CBZ than in the VPA subjects (p< 0.05). Monitoring serum fT4 levels is suggested during CBZ treatment to detect subclinical hypothyroidism. Although secondary hyperparathyroidism was observed in 13 % of the study patients, bone mineral density measurements were unaffected. It is important to note that these results were obtained in ambulatory children with epilepsy. We conclude that the long term effects of subclinical hypothyroidism and secondary hyperparathyroidism should be closely monitored in patients receiving these drugs.

Keywords:

Epilepsy, Thyroid Function Tests, Thyroid Hormones, Lipid Metabolism, Valproic Acid, Anticonvulsants, Carbamazepine,

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