Comparison of Levothyroxine Dosing in Patients with and without Heart Failure

Yang, Tianrui; Ruegger, Melanie; Colavecchia, A. Carmine; Sadhu, Archana R.; Patham, Bhargavi; Tatara, Alexandra W.

doi:10.1080/07435800.2019.1645165

Cited by 1 publication

(1 citation statement)

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“…Fraczek-Jucha et al reported that serum Se and FT3 levels were not correlated even when the prevalence of Se deficiency was high (74.6%) [ 109 ]. Yang et al single-centre study of a cohort of ambulatory patients in the US found that the dose of LT4 did not differ significantly when comparing patients with heart failure vs. those without [ 110 ]. Lastly, Chakrabarti et al found that serum malondialdehyde levels (a marker of oxidative stress) fell during treatment with LT4 [ 111 ].…”

Section: Resultsmentioning

confidence: 99%

Factors influencing the levothyroxine dose in the hormone replacement therapy of primary hypothyroidism in adults

Caron

Grunenwald

Persani

et al. 2021

Rev Endocr Metab Disord

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Levothyroxine (LT4) is a safe, effective means of hormone replacement therapy for hypothyroidism. Here, we review the pharmaceutical, pathophysiological and behavioural factors influencing the absorption, distribution, metabolism and excretion of LT4. Any factor that alters the state of the epithelium in the stomach or small intestine will reduce and/or slow absorption of LT4; these include ulcerative colitis, coeliac disease, bariatric surgery, Helicobacter pylori infection, food intolerance, gastritis, mineral supplements, dietary fibre, resins, and various drugs. Once in the circulation, LT4 is almost fully bound to plasma proteins. Although free T4 (FT4) and liothyronine concentrations are extensively buffered, it is possible that drug- or disorder-induced changes in plasma proteins levels can modify free hormone levels. The data on the clinical significance of genetic variants in deiodinase genes are contradictory, and wide-scale genotyping of hypothyroid patients is not currently justified. We developed a decision tree for the physician faced with an abnormally high thyroid-stimulating hormone (TSH) level in a patient reporting adequate compliance with the recommended LT4 dose. The physician should review medications, the medical history and the serum FT4 level and check for acute adrenal insufficiency, heterophilic anti-TSH antibodies, antibodies against gastric and intestinal components (gastric parietal cells, endomysium, and tissue transglutaminase 2), and Helicobacter pylori infection. The next step is an LT4 pharmacodynamic absorption test; poor LT4 absorption should prompt a consultation with a gastroenterologist and (depending on the findings) an increase in the LT4 dose level. An in-depth etiological investigation can reveal visceral disorders and, especially, digestive tract disorders.

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Section: Resultsmentioning

confidence: 99%