Liquid levothyroxine sodium therapy improves pharmacologic thyroid-stimulating hormone homeostasis in patients with reduced efficacy for tablet levothyroxine sodium after sleeve gastrectomy. A case report

Abstract

Hypothyroidism is a common disorder in patients withmorbid obesity [1]. Levothyroxine (L-T4) sodium monotherapy is the primary treatment for hypothyroidism [2]. Bariatric surgery (BS) is effective in the long-term treatment of morbid obesity and its associated comorbidities with sleeve gastrectomy (SG) representing one of the most performed bariatric surgical procedures [3]. L-T4 sodium is the sodium salt of levothyroxine, a synthetic levoisomer of thyroxine that is similar to the endogenous hormone produced by the thyroid gland. Traditionally, it is prescribed in tablet form and is absorbed in the small intestine, mainly in the jejunum and the ileum [4]. Evidence confirms that the stomach has a prerequisite role in the efficient absorption of tablet L-T4 sodium [5]. Furthermore, other factors such as gastric emptying time, and the use of proton pump inhibitor (PPIs) may affect L-T4 sodium absorption [5]. Recent reports have documented changes in L-T4 sodium absorption after gastric bypass, whereas limited data are available on SG [6]. Fain et al. report a case of a 35-year-old woman who received a total thyroidectomy followed by SG 2 years later, who was euthyroid on L-T4 sodium replacement. However, 8 months after SG, she showed a huge increase in thyroid-stimulating hormone (TSH) levels and signs of hypothyroidism. Despite therapy adjustments, her TSH levels and hypothyroidism did not resolve until the L-T4 sodium was crushed before oral intake [7]. Herein, we present the case of a 34-year-old woman with a history of hypothyroidism who was euthyroid and on daily tablets of L-T4 sodium at the time of the SG and who developed altered TSH levels a few weeks postoperatively. TSH values are normalized by switching the patient from tablet to liquid formulation. To our knowledge, this is the first case report in which the alteration of TSH following SG was intercepted and treated early and successfully by switching from tablet to liquid L-T4 sodium formulation before the occurrence of hypothyroidism.