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Journal of Pediatric Endocrinology and Metabolism

Editor-in-Chief: Kiess, Wieland

Editorial Board Member: Darendeliler, Feyza / Gustafsson, Jan / Luo, Feihong / Mericq, Veronica / Lanes M. D., Roberto / Battelino, Tadej / Buyukgebiz, Atilla / Cassorla, Fernando / Chrousos, George P. / Cutfield, Wayne / Fideleff, Hugo L. / Hershkovitz, Eli / LaFranchi, Stephen H. / Mohn, Angelika / Root, Allen W. / Rosenfeld, Ron G. / Wabitsch, Martin / Werther, George / Zadik, Zvi

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In congenital hypothyroidism, an initial L-thyroxine dose of 10–12 μg/kg/day is sufficient and sometimes excessive based on thyroid tests 1 month later

1 / Meenal Pathak2 / Paul B. Kaplowitz2

1Pediatric Endocrinology, Children’s National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010, USA

2Department of Endocrinology, Children’s National Medical Center, Washington, DC, USA

Corresponding author: Priya Vaidyanathan, Pediatric Endocrinology, Children’s National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010, USA

Citation Information: Journal of Pediatric Endocrinology and Metabolism. Volume 25, Issue 9-10, Pages 849–852, ISSN (Online) 2191-0251, ISSN (Print) 0334-018X, DOI: 10.1515/jpem-2012-0025, September 2012

Publication History

Published Online:


Background: Current guidelines recommend an initial L-thyroxine (L-T4) dose of 10–15 μg/kg/day for the treatment of congenital hypothyroidism (CH). We analyzed our data for the treatment outcome at 1 month after we noted a frequent overtreatment even at the lower end of this dose range.

Methods: A 3-year chart review of 55 patients with confirmed CH was performed. The patients were divided to three groups based on L-T4 dose: Group 1 (6–9.9 μg/kg), Group 2 (10–11.9 μg/kg), and Group 3 (12–15 μg/kg). Overtreatment was defined as T4>16 μg/dL/free T4>2.3 ng/dL±thyroid-stimulating hormone (TSH) <0.5 μIU/L and undertreatment was defined as TSH>6 μIU/L at 1 month.

Results: At 1 month, 45.8%, 37.5%, and 16.6% in Group 1, 30%, 55%, and 15% in Group 2, and 0%, 75%, and 25% in Group 3 had target labs, overtreatment, and undertreatment, respectively.

Conclusions: An initial L-T4 dose of 10–11.9 μg/kg for TSH>100 μIU/L and 8–10 μg/kg for TSH<100 μIU/L at diagnosis met and often exceeded the target thyroid levels at 1 month. More frequent overtreatment was seen when >12 μg/kg was given.

Keywords: congenital; hypothyroidism; L-thyroxine dose

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