title: Resistance to levothyroxine in a bariatric surgery patient: an indication for liquid formulation?
abstract: We report the case of a 49-year-old female patient with hypothyroidism who underwent bariatric surgery and developed severe hypothyroidism despite high doses of oral levothyroxine (L-T4) tablets. Initially, a high-dose L-T4 tablets absorption test was performed to exclude pseudo-malabsorption. In view of a modest increase in serum T4 levels, L-T4 liquid formulation absorption test was performed, and showed faster and more efficient absorption of thyroid hormones. We discuss the issue of distinguishing malabsorption from pseudo-malabsorption, review the literature concerning the benefits of liquid L-T4 in cases of impaired absorption such as bariatric surgery and consider the socio-economic implications of different liquid formulations.
authors.affiliation: a Service d'Endocrinologie, CHU UcL Namur, Yvoir , Belgium.|b Service de Médecine Interne , Université catholique de Louvain , Brussels , Belgium.
authors.forename: Christophe
authors.initials: C
authors.lastname: Hommel
authors.affiliation: a Service d'Endocrinologie, CHU UcL Namur, Yvoir , Belgium.
authors.forename: Etienne
authors.initials: E
authors.lastname: Delgrange
mesh_terms: D050110:Bariatric Surgery; D004351:Drug Resistance; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000188:drug therapy*; D008875:Middle Aged; D011183:Postoperative Complications / Q000188:drug therapy*; D013974:Thyroxine / Q000008:administration & dosage*
chemical_list: D013974:Thyroxine
keywords: BMI, Body mass index; Bariatric surgery; L-T4, Levothyroxine; Levothyroxine; Liquid formulation; Malabsorption; PPI, Proton pump inhibitors; Pseudo-malabsorption