<scp>l</scp>-Thyroxine plus Liothyronine in Hypothyroidism
Authors: José I. Botella-Carretero, Héctor F. Escobar-Morreale
Journal: Annals of Internal Medicine (2005)

Letters4 October 2005l-Thyroxine plus Liothyronine in HypothyroidismJosé I. Botella-Carretero, MD, PhD and Héctor F. Escobar-Morreale, MD, PhDJosé I. Botella-Carretero, MD, PhDFrom Hospital Ramón y Cajal, E-28034 Madrid, Spain.Search for more papers by this author and Héctor F. Escobar-Morreale, MD, PhDFrom Hospital Ramón y Cajal, E-28034 Madrid, Spain.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-143-7-200510040-00018 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail IN RESPONSE:We are certainly aware that there are differences in the effects of l-thyroxine and liothyronine. In fact, several studies by our group have shown that the addition of liothyronine to l-thyroxine is essential to ensure euthyroidism in plasma and all tissues of thyroidectomized rats (1-3). However, thyroid hormone physiology is quite different in humans. This might help explain why, contrary to the expectations raised by our previous animal data, our study in hypothyroid patients and most similar studies conducted to date failed to demonstrate any objective advantage of combined l-thyroxine plus liothyronine replacement therapy over standard treatment with ...References1. Escobar-Morreale HF, Obregón MJ, Escobar del Rey F, Morreale de Escobar G. Replacement therapy for hypothyroidism with thyroxine alone does not ensure euthyroidism in all tissues, as studied in thyroidectomized rats. J Clin Invest. 1995;96:2828-38. [PMID: 8675653] CrossrefMedlineGoogle Scholar2. Escobar-Morreale HF, Escobar del Rey F, Obregón MJ, Morreale de Escobar G. Only the combined treatment with thyroxine and triiodothyronine ensures euthyroidism in all tissues of the thyroidectomized rat. Endocrinology. 1996;137:2490-502. [PMID: 8641203] CrossrefMedlineGoogle Scholar3. Escobar-Morreale HF, Obregón MJ, Hernandez A, Escobar del Rey F, Morreale de Escobar G. Regulation of iodothyronine deiodinase activity as studied in thyroidectomized rats infused with thyroxine or triiodothyronine. Endocrinology. 1997;138:2559-68. [PMID: 9165049] CrossrefMedlineGoogle Scholar4. Siegmund W, Spieker K, Weike AI, Giessmann T, Modess C, Dabers T, et al. Replacement therapy with levothyroxine plus triiodothyronine (bioavailable molar ratio 14 : 1) is not superior to thyroxine alone to improve well-being and cognitive performance in hypothyroidism. Clin Endocrinol (Oxf). 2004;60:750-7. [PMID: 15163340] CrossrefMedlineGoogle Scholar Author, Article, and Disclosure InformationAuthors: José I. Botella-Carretero, MD, PhD; Héctor F. Escobar-Morreale, MD, PhDAffiliations: From Hospital Ramón y Cajal, E-28034 Madrid, Spain.Disclosures: Merck Darmstadt KgAa provided free of charge the l-thyroxine plus liothyronine combinations used in the study, as well as financial aid for part of the expenses of the trial. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoThyroid Hormone Replacement Therapy in Primary Hypothyroidism: A Randomized Trial Comparing l-Thyroxine plus Liothyronine with l-Thyroxine Alone Héctor F. Escobar-Morreale , José I. Botella-Carretero , Manuel Gómez-Bueno , José M. Galán , Vivencio Barrios , and José Sancho l-Thyroxine plus Liothyronine in Hypothyroidism Jean Eisinger Metrics 4 October 2005Volume 143, Issue 7Page: 543-544KeywordsDrug therapyHeartHypothyroidismMotivationMuscle functionsPharmacokineticsSkeletal musclesThyroid hormonesThyroidectomyThyroxine ePublished: 4 October 2005 Issue Published: 4 October 2005 Copyright & PermissionsCopyright © 2005 by American College of Physicians. All Rights Reserved.PDF downloadLoading ...