LEVOTHYROXINE PHARMACOKINETICS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 这项研究由NlCHD产科和药理学研究部资助，是一项前瞻性、多中心、开放标签、非随机、孕前、孕期和产后的药代动力学研究。左旋甲状腺素(LT4)将在补充甲状腺功能减退的非妊娠和妊娠妇女中进行药代动力学研究。合成左旋甲状腺素钠(LT4)补充剂 可能需要在整个怀孕期间增加。由于妊娠6周时甲状腺激素浓度增加了约50%，因此认为补充量至少应增加50%。然而，关于怀孕期间适当的LT4剂量以及是否 在妊娠的不同阶段，剂量应该改变，以优化疗效。其次，预防胎儿神经发育不良所需的最低限度的LT4补充量尚不清楚。PIS建议使用稳定同位素研究LT4单剂量药代动力学 方法论。参与这项研究的女性将继续接受正常的药物治疗。他们还将被给予一种特殊的标记，称为“稳定同位素”，这样研究小组就可以跟随甲状旁腺素的补充。稳定的同位素将只在孕前(或产后)探视期间和孕期探视期间使用一次。稳定同位素没有有害或辐射影响；测试 已经证明它们在新生儿中是安全的，并且已经在研究中使用了20多年

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study, funded by the Obstetrics and Pharmacology Research Unit of NlCHD, is a prospective, multi-center, open-label, non-randomized, pharmacokinetic study before pregnancy, during pregnancy and the postpartum period. Pharmacokinetics of levothyroxine (LT4) will be conducted in supplemented hypothyroid non-pregnant and pregnant women. Synthetic levothyroxine sodium (LT4) supplementation may need to be increased throughout pregnancy. Since Thyroid Hormone concentration increases by approximately 50% by Gestational Week 6 it is thought that supplementation should be increased by at least 50%. However, little is known regarding the appropriate LT4 dosing in pregnancy, and whether dosing should change throughout the different stages of gestation to optimize efficacy. Secondly, the minimal LT4 supplementation needed to prevent adverse neuro-developmental effects in the fetus is not known. The PIs propose to investigate LT4 single dose pharmacokinetics using stable isotope methodology. Women participating in this study will continue on their normal medication. They will also be given a special marker called a "stable isotope" so that the study team can follow fevothyroxine supplementation. The stable isotope will be given only once during the pre-pregnancy {or post-partum) visit and once during the pregnancy visit. Stable isotopes have no harmful or radiation effects; tests have shown them to be safe in newborn infants and they have been used for over 20 years in studies