{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T14:17:41Z","timestamp":1784557061207,"version":"3.55.0"},"reference-count":28,"publisher":"Bioscientifica","license":[{"start":{"date-parts":[[2019,3,21]],"date-time":"2019-03-21T00:00:00Z","timestamp":1553126400000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":["edm.bioscientifica.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2019,3,21]]},"abstract":"<jats:title>Summary<\/jats:title>\n                  <jats:p>\n                    Reduced intestinal absorption of levothyroxine (LT4) is the most common cause of failure to achieve an adequate therapeutic target in hypothyroid patients under replacement therapy. We present the case of a 63-year-old woman with autoimmune hypothyroidism previously well-replaced with tablet LT4 who became unexpectedly no more euthyroid. At presentation, the patient reported the onset of acute gastrointestinal symptoms characterized by nausea, loss of appetite, flatulence, abdominal cramps and diarrhea, associated with increase of thyrotropin levels (TSH: 11\u2009mIU\/mL). Suspecting a malabsorption disease, a thyroxine solid-to-liquid formulation switch, at the same daily dose, was adopted to reach an optimal therapeutic target despite the gastrointestinal symptoms persistence. Oral LT4 solution normalized thyroid hormones. Further investigations diagnosed giardiasis, and antibiotic therapy was prescribed. This case report is compatible with a malabsorption syndrome caused by an intestinal parasite (\n                    <jats:italic>Giardia lamblia<\/jats:italic>\n                    ). The reduced absorption of levothyroxine was resolved by LT4 oral solution.\n                  <\/jats:p>\n                  <jats:sec>\n                    <jats:title>Learning points:<\/jats:title>\n                    <jats:list list-type=\"bullet\">\n                      <jats:list-item>\n                        <jats:p>The failure to adequately control hypothyroidism with oral levothyroxine is a common clinical problem.<\/jats:p>\n                      <\/jats:list-item>\n                      <jats:list-item>\n                        <jats:p>Before increasing levothyroxine dose in a patient with hypothyroidism previously well-controlled with LT4 tablets but no more in appropriate therapeutic target, we suggest to investigate non adhesion to LT4 therapy, drug or food interference with levothyroxine absorption, intestinal infection, inflammatory intestinal disease, celiac disease, lactose intolerance, short bowel syndrome after intestinal or bariatric surgery, hepatic cirrhosis and congestive heart failure.<\/jats:p>\n                      <\/jats:list-item>\n                      <jats:list-item>\n                        <jats:p>LT4 oral solution has a better absorptive profile than the tablet. In hypothyroid patients affected by malabsorption syndrome, switch of replacement therapy from tablet to liquid LT4 should be tested before increasing the dose of LT4.<\/jats:p>\n                      <\/jats:list-item>\n                    <\/jats:list>\n                  <\/jats:sec>","DOI":"10.1530\/edm-19-0026","type":"journal-article","created":{"date-parts":[[2019,3,21]],"date-time":"2019-03-21T08:11:03Z","timestamp":1553155863000},"update-policy":"https:\/\/doi.org\/10.1530\/crossmarkpolicy-2","source":"Crossref","is-referenced-by-count":10,"title":["Switch from tablet levothyroxine to oral solution resolved reduced absorption by intestinal parasitosis"],"prefix":"10.1530","volume":"2019","author":[{"given":"Anna","family":"Tortora","sequence":"first","affiliation":[{"name":"Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Salerno, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Domenico","family":"La Sala","sequence":"additional","affiliation":[{"name":"Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Salerno, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mario","family":"Vitale","sequence":"additional","affiliation":[{"name":"Department of Medicine, Surgery and Dentistry, University of Salerno, Baronissi, Salerno, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"416","reference":[{"key":"ref181","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1089\/thy.2007.0222","article-title":"Altered intestinal absorption of L-thyroxine caused by coffee","volume":"18","year":"2008","journal-title":"Thyroid"},{"key":"ref141","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1089\/thy.1991.1.241","article-title":"Localization of human thyroxine absorption","volume":"1","year":"1991","journal-title":"Thyroid"},{"key":"ref271","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1051\/parasite\/2008153261","article-title":"Pathophysiology of enteric infections with Giardia duodenalis","volume":"15","year":"2008","journal-title":"Parasite"},{"key":"ref01","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1089\/thy.1991.1.241","article-title":"Localization of human thyroxine absorption","volume":"1","year":"1991","journal-title":"Thyroid"},{"key":"ref11","first-page":"40","article-title":"A review of the pharmacokinetics of levothyroxine for the treatment of hypothyroidism","volume":"9","year":"2013","journal-title":"European Endocrinology"},{"key":"ref221","doi-asserted-by":"crossref","first-page":"10331","DOI":"10.3748\/wjg.v20.i30.10331","article-title":"Helicobacter pylori infection and drugs malabsorption","volume":"20","year":"2014","journal-title":"World Journal of Gastroenterology"},{"key":"ref231","first-page":"1487","article-title":"Impaired intestinal absorption of thyroid hormone in a case of Hashimoto\u2019s disease with anti-T3 and anti-T4","volume":"58","year":"1982","journal-title":"Nippon Naibunpi Gakkai Zasshi"},{"key":"ref131","doi-asserted-by":"crossref","first-page":"261","DOI":"10.1051\/parasite\/2008153261","article-title":"Pathophysiology of enteric infections with Giardia duodenalis","volume":"15","year":"2008","journal-title":"Parasite"},{"key":"ref251","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1590\/S0004-27302011000100012","article-title":"Increased levothyroxine requirement in a woman with previously well-controlled hypothyroidism and intestinal giardiasis","volume":"55","year":"2011","journal-title":"Arquivos Brasileiros de Endocrinologia e Metabologia"},{"key":"ref91","first-page":"1487","article-title":"Impaired intestinal absorption of thyroid hormone in a case of Hashimoto\u2019s disease with anti-T3 and anti-T4","volume":"58","year":"1982","journal-title":"Nippon Naibunpi Gakkai Zasshi"},{"key":"ref101","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1111\/j.1467-789X.2009.00614.x","article-title":"A systematic review of drug absorption following bariatric surgery and its theoretical implications","volume":"11","year":"2010","journal-title":"Obesity Reviews"},{"key":"ref81","doi-asserted-by":"crossref","first-page":"10331","DOI":"10.3748\/wjg.v20.i30.10331","article-title":"Helicobacter pylori infection and drugs malabsorption","volume":"20","year":"2014","journal-title":"World Journal of Gastroenterology"},{"key":"ref171","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1210\/er.2018-00168","article-title":"Gastrointestinal malabsorption of thyroxine","volume":"40","year":"2019","journal-title":"Endocrine Reviews"},{"key":"ref51","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1007\/s12020-016-1035-1","article-title":"Liquid and softgel levothyroxine use in clinical practice: state of the art","volume":"54","year":"2016","journal-title":"Endocrine"},{"key":"ref211","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1080\/17425247.2017.1290604","article-title":"Oral liquid levothyroxine solves the problem of tablet levothyroxine malabsorption due to concomitant intake of multiple drugs","volume":"14","year":"2017","journal-title":"Expert Opinion on Drug Delivery"},{"key":"ref161","doi-asserted-by":"crossref","first-page":"3905","DOI":"10.1210\/jc.2009-0860","article-title":"Timing of levothyroxine administration affects serum thyrotropin concentration","volume":"94","year":"2009","journal-title":"Journal of Clinical Endocrinology and Metabolism"},{"key":"ref111","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1590\/S0004-27302011000100012","article-title":"Increased levothyroxine requirement in a woman with previously well-controlled hypothyroidism and intestinal giardiasis","volume":"55","year":"2011","journal-title":"Arquivos Brasileiros de Endocrinologia e Metabologia"},{"key":"ref151","first-page":"40","article-title":"A review of the pharmacokinetics of levothyroxine for the treatment of hypothyroidism","volume":"9","year":"2013","journal-title":"European Endocrinology"},{"key":"ref71","doi-asserted-by":"crossref","first-page":"467","DOI":"10.1080\/17425247.2017.1290604","article-title":"Oral liquid levothyroxine solves the problem of tablet levothyroxine malabsorption due to concomitant intake of multiple drugs","volume":"14","year":"2017","journal-title":"Expert Opinion on Drug Delivery"},{"key":"ref21","doi-asserted-by":"crossref","first-page":"3905","DOI":"10.1210\/jc.2009-0860","article-title":"Timing of levothyroxine administration affects serum thyrotropin concentration","volume":"94","year":"2009","journal-title":"Journal of Clinical Endocrinology and Metabolism"},{"key":"ref241","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1111\/j.1467-789X.2009.00614.x","article-title":"A systematic review of drug absorption following bariatric surgery and its theoretical implications","volume":"11","year":"2010","journal-title":"Obesity Reviews"},{"key":"ref121","first-page":"180","article-title":"Chronic intestinal giardiasis with isolated levothyroxine malabsorption as reason for severe hypothyroidism implications for localization of thyroid hormone absorption in the gut","volume":"104","year":"1996","journal-title":"Experimental and Clinical Endocrinology and Diabetes"},{"key":"ref31","doi-asserted-by":"crossref","first-page":"118","DOI":"10.1210\/er.2018-00168","article-title":"Gastrointestinal malabsorption of thyroxine","volume":"40","year":"2019","journal-title":"Endocrine Reviews"},{"key":"ref191","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1007\/s12020-016-1035-1","article-title":"Liquid and softgel levothyroxine use in clinical practice: state of the art","volume":"54","year":"2016","journal-title":"Endocrine"},{"key":"ref201","doi-asserted-by":"crossref","first-page":"1103","DOI":"10.1517\/17425247.2014.918101","article-title":"The administration of L-thyroxine as soft gel capsule or liquid solution","volume":"11","year":"2014","journal-title":"Expert Opinion on Drug Delivery"},{"key":"ref261","first-page":"180","article-title":"Chronic intestinal giardiasis with isolated levothyroxine malabsorption as reason for severe hypothyroidism implications for localization of thyroid hormone absorption in the gut","volume":"104","year":"1996","journal-title":"Experimental and Clinical Endocrinology and Diabetes"},{"key":"ref41","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1089\/thy.2007.0222","article-title":"Altered intestinal absorption of L-thyroxine caused by coffee","volume":"18","year":"2008","journal-title":"Thyroid"},{"key":"ref61","doi-asserted-by":"crossref","first-page":"1103","DOI":"10.1517\/17425247.2014.918101","article-title":"The administration of L-thyroxine as soft gel capsule or liquid solution","volume":"11","year":"2014","journal-title":"Expert Opinion on Drug Delivery"}],"container-title":["Endocrinology, Diabetes &amp; Metabolism Case Reports"],"original-title":[],"link":[{"URL":"https:\/\/edm.bioscientifica.com\/view\/journals\/edm\/2019\/1\/EDM19-0026.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/edm.bioscientifica.com\/downloadpdf\/journals\/edm\/2019\/1\/EDM19-0026.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,20]],"date-time":"2026-07-20T13:47:04Z","timestamp":1784555224000},"score":1,"resource":{"primary":{"URL":"http:\/\/journals.bioscientifica.com\/edm\/article\/35393"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,3,21]]},"references-count":28,"URL":"https:\/\/doi.org\/10.1530\/edm-19-0026","relation":{},"ISSN":["2052-0573"],"issn-type":[{"value":"2052-0573","type":"electronic"}],"subject":[],"published":{"date-parts":[[2019,3,21]]}}}