Thyroxine Bioequivalency
Authors: BARRY A. WARNER
Journal: Annals of Internal Medicine (1985)

Letters and Corrections1 October 1985Thyroxine BioequivalencyBARRY A. WARNER, M.D., RICARDO DEGUZMAN, M.D.BARRY A. WARNER, M.D.Search for more papers by this author, RICARDO DEGUZMAN, M.D.Search for more papers by this authorAuthor, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-103-4-646_2 SectionsAboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail ExcerptTo the editor: The article by Hennessey and associates (1) on thyroxine equivalency has provided insight into this confusing issue. An important effect of this study would be to improve the pharmaceutical products clinicians assume to be equivalent.However, whether the authors have succeeded in providing "accurate and practical guidelines to all physicians prescribing thyroxine" is not completely resolved. We caution readers to consider the effect the time of blood sampling after thyroxine ingestion has on thyroid function test results. Using different techniques, Symons and Murphy (2) and Deam and associates (3) have shown variations of as much as 50%...References1. HENNESSEYBURMANWARTOFSKY JKL. The equivalency of two L-thyroxine preparations. Ann Intern Med. 1985;102:770-3. LinkGoogle Scholar2. SYMONSMURPHY RL. Acute changes in thyroid function tests following ingestion of thyroxine. Clin Endocrinol. 1983;19:539-46. CrossrefMedlineGoogle Scholar3. DEAMCAMPBELLRATNAIKE DDS. Effect of oral intake of thyroxine on results of thyroid function tests in patients receiving thyroid replacement therapy. Med J Aust. 1983;2:374-6. CrossrefMedlineGoogle Scholar4. LARSENSILVAKAPLAN PJM. Relationships between circulating and intracellular thyroid hormones; physiological and clinical implications. Endocrinol Rev. 1981;2:87-102. CrossrefMedlineGoogle Scholar5. LARSEN P. Salicylate-induced increases in free triiodothyronine in human serum. J Clin Invest. 1972;51:1125-33. CrossrefMedlineGoogle Scholar6. LUMNICOLOFFSPENCERKAPTEIN SJCE. Peripheral tissue mechanism for maintenance of serum triiodothyronine values in a thyroxine-deficient state in man. J Clin Invest. 1984;73:570-5. CrossrefMedlineGoogle Scholar1. HENNESSEYBURMANWARTOFSKY JKL. The equivalency of two L-thyroxine preparations. Ann Intern Med. 1985;102:770-3. LinkGoogle Scholar1. SYMONSMURPHY RL. Acute changes in thyroid function tests following ingestion of thyroxine. Clin Endocrinol. 1983;19:539-46. CrossrefMedlineGoogle Scholar2. LEBOFFKAPLANSILVALARSEN MMJP. Bioavailability of thyroid hormones from oral replacement preparations. Metabolism. 1982;31:900-5. CrossrefMedlineGoogle Scholar This content is PDF only. To continue reading please click on the PDF icon. Author, Article, and Disclosure InformationAffiliations: Wright State University School of Medicine Dayton, OH 45428 PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics Cited ByL-Thyroxine Dosage: A Reevaluation of Therapy with Contemporary PreparationsJAMES V. HENNESSEY, M.D., JUDY E. EVAUL, M.S.P.H., YUEH-CHU TSENG, Ph.D., KENNETH D. BURMAN, M.D., LEONARD WARTOFSKY, M.D. 1 October 1985Volume 103, Issue 4Page: 646-647KeywordsHematologic testsIngestionThyroidThyroxine Issue Published: 1 October 1985 PDF DownloadLoading ...