Calcium Carbonate–Induced Hypothyroidism
Authors: Lorie E. Butner, Patricia Pecora Fulco, George Feldman
Journal: Annals of Internal Medicine (2000)

Letters4 April 2000Calcium Carbonate–Induced HypothyroidismLorie E. Butner, PharmD, Patricia Pecora Fulco, PharmD, BCPS, and George Feldman, MDLorie E. Butner, PharmDMedical University of South Carolina; Charleston, SC 29425 (Butner)Medical College of Virginia Hospitals; Richmond, VA 23298 (Fulco)Medical College of Virginia Hospitals; McGuire Veterans Affairs Medical Center; Richmond, VA 23298 (Feldman), Patricia Pecora Fulco, PharmD, BCPSMedical University of South Carolina; Charleston, SC 29425 (Butner)Medical College of Virginia Hospitals; Richmond, VA 23298 (Fulco)Medical College of Virginia Hospitals; McGuire Veterans Affairs Medical Center; Richmond, VA 23298 (Feldman), and George Feldman, MDMedical University of South Carolina; Charleston, SC 29425 (Butner)Medical College of Virginia Hospitals; Richmond, VA 23298 (Fulco)Medical College of Virginia Hospitals; McGuire Veterans Affairs Medical Center; Richmond, VA 23298 (Feldman)Author, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-132-7-200004040-00026 SectionsAboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail TO THE EDITOR:Several drug and food interactions have been reported with l-thyroxine (1, 2). Many of these interactions occur in the small intestine, leading to impaired l-thyroxine absorption (2). These interactions may lead to clinical hypothyroidism. The following case report describes this circumstance.A 49-year-old woman with a history of pseudotumor cerebri, hypothyroidism, and gastric bypass surgery was admitted for an episode of bradycardia and syncope while undergoing an upper gastrointestinal study. Upon further evaluation, the patient reported headache, dizziness, mood changes, depression, and lethargy. Hypothyroidism was suspected, and the thyroid-stimulating hormone (TSH) concentration measured on admission was 21.85 ...References1. Sherman SL, Malecha SE. Absorption and malabsorption of levothyroxine sodium. Am J Therap. 1995;2:814-8. CrossrefMedlineGoogle Scholar2. Hays MT. Localization of human thyroxine absorption. Thyroid. 1991;1:241-8. CrossrefMedlineGoogle Scholar3. Halverson JD. Vitamin and mineral deficiencies following obesity surgery. Gastroenterol Clin North Am. 1987;16:307-15. CrossrefMedlineGoogle Scholar4. Azizi F, Belur R, Albano J. Malabsorption of thyroid hormones after jejunoileal bypass for obesity. Ann Intern Med. 1979;90:941-2. LinkGoogle Scholar5. Schneyer CR. Calcium carbonate and reduction of levothyroxine efficacy [Letter]. JAMA. 1998;279:750. CrossrefMedlineGoogle Scholar Author, Article, and Disclosure InformationAffiliations: Medical University of South Carolina; Charleston, SC 29425 (Butner)Medical College of Virginia Hospitals; Richmond, VA 23298 (Fulco)Medical College of Virginia Hospitals; McGuire Veterans Affairs Medical Center; Richmond, VA 23298 (Feldman) PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetails Metrics Cited ByPhosphate binders as a cause of hypothyroidism in dialysis patients: practical indications from a review of the literatureFactors Affecting Gastrointestinal Absorption of Levothyroxine: A ReviewThyroid hormonesIODINE AND DRUGS THAT AFFECT THYROID FUNCTIONl -Thyroxine Requirement in Patients with Autoimmune Hypothyroidism and Parietal Cell AntibodiesUse of Self-Prescribed Nonprescription Medications and Dietary Supplements Among Assisted Living Facility ResidentsThyroid hormonesThyroid hormones and antithyroid drugsExaggerated Levothyroxine Malabsorption Due to Calcium Carbonate Supplementation in Gastrointestinal Disorders 4 April 2000Volume 132, Issue 7Page: 595KeywordsAttentionCalciumCarbonatesDrug interactionsHypothyroidismSmall intestineSurgerySyncopeThyroid-stimulating hormoneThyroxine Issue Published: 4 April 2000 CopyrightCopyright © 2000 by American College of Physicians. All Rights Reserved.PDF DownloadLoading ...