LEVOTHYROXINE PHARMACOKINETICS

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。所列机构为 中心，不一定是研究者的机构。 本研究由NlCHD的产科和药理学研究单位资助，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。将在补充甲状腺功能减退症的非妊娠和妊娠女性中进行左甲状腺素（LT 4）的药代动力学研究。合成左旋甲状腺素钠（LT 4）补充剂 可能需要在整个怀孕期间增加。由于甲状腺激素浓度增加了约50%，在第6周，它被认为是补充应增加至少50%。然而，关于妊娠期适当的LT 4剂量，以及是否 在整个妊娠的不同阶段，剂量应该改变以优化功效。其次，目前尚不清楚预防胎儿神经发育不良影响所需的最低限度LT 4补充剂。PI建议使用稳定同位素研究LT 4单次给药的药代动力学 方法论参与本研究的女性将继续正常用药。他们还将被给予一种称为“稳定同位素”的特殊标记物，以便研究小组可以跟踪fevotyroxine补充剂。稳定同位素仅在孕前（或产后）访视期间和妊娠访视期间给予一次。稳定同位素没有有害或辐射影响;测试 已经证明它们对新生儿是安全的，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