Liewendahl K, Tikanoja S, Helenius T, Majuri H
Clin Chem. 1985 Dec;31(12):1993-6.
We measured free thyroxin (FT4) and free triiodothyronine (FT3) in serum of patients taking the anti-epileptic drugs phenytoin and carbamazepine, both by equilibrium dialysis procedures and analog-type radioimmunoassays. By either assay, the mean concentration of FT4 was significantly decreased in patients receiving either drug, whereas their FT3 concentrations were normal or only slightly decreased. Adding therapeutic concentrations of these drugs in vitro to control sera had a small or no incremental effect on FT4 and FT3 as measured by either method, but adding greater concentrations of the drugs in vitro markedly increased the concentrations of the free hormones. These results indicate that the main mechanism of the decrease in concentrations of free thyroid hormones in serum during therapy with anticonvulsant drugs is not the displacement of hormones from their binding to plasma proteins. We also determined, using a new and sensitive immunoradiometric assay, that patients taking carbamazepine, but not those taking phenytoin, had significantly less thyrotropin in the serum.
我们采用平衡透析法和模拟型放射免疫分析法，测定了服用抗癫痫药物苯妥英和卡马西平患者血清中的游离甲状腺素（FT4）和游离三碘甲状腺原氨酸（FT3）。无论采用哪种检测方法，接受这两种药物治疗的患者血清FT4平均浓度均显著降低，而其FT3浓度正常或仅略有降低。体外向对照血清中添加治疗浓度的这些药物，两种检测方法测得的FT4和FT3水平仅有轻微升高或无升高，但添加更高浓度的药物则显著提高了游离激素的浓度。这些结果表明，抗惊厥药物治疗期间血清中游离甲状腺激素浓度降低的主要机制并非激素从与血浆蛋白的结合中被置换出来。我们还采用一种新型灵敏免疫放射分析法测定发现，服用卡马西平的患者血清促甲状腺激素显著减少，而服用苯妥英的患者则不然。
