TY - JOUR AU - Gokosmanoglu, Feyzi AU - Onmez, Attila PY - 2020/12/28 Y2 - 2024/03/29 TI - Changes in levothyroxine pharmacokinetics following bariatric surgery in obese hypothyroid patients JF - EXPERIMENTAL BIOMEDICAL RESEARCH JA - Exp Biomed Res VL - 4 IS - 1 SE - Articles DO - 10.30714/j-ebr.2021165777 UR - https://experimentalbiomedicalresearch.com/ojs/index.php/ebr/article/view/140 SP - 16-22 AB - <p><strong>Aim: </strong>Levothyroxine (L-T4) requirements in obese hypothyroid patients receiving L-T4 therapy decrease following bariatric surgery. L-T4 absorption is also thought to decrease after surgery. The purpose of this study was to evaluate L-T4 requirements in hypothyroidism cases before and after weight loss through bariatric surgery.</p><p><strong>Methods:</strong> Seventy-six cases of hypothyroidism receiving L-T4 replacement therapy and with a body mass index over 40 kg/m2 were included in the study. Patients losing at least 10% of basal body weight following bariatric surgery were assessed in terms of thyroid hormone levels and L-T4 requirements over follow-up of at least one year. The L-T4 requirements of patients in whom euthyroidism was achieved were compared in terms of bariatric surgery procedures and hypothyroidism etiology.</p><p><strong>Results: </strong>Seventy-six patients (56 women, 20 men) with a mean age of 38 years (18-51) were included in the study. Mean weight before bariatric surgery was 121.6 ± 6.8 kg, and mean body mass index was 49.5 ± 1.6 kg/m<sup>2</sup>. Euthyroidism was confirmed at pre- and post-bariatric surgery evaluation. No statistically significant postoperative changes were determined in thyroid-stimulating hormone or free thyroxine-3 and -4 (<em>p </em>&gt; 0.05). A statistically insignificant decrease was observed in L-T4 dosages after surgery in cases of Hashimoto’s thyroiditis (<em>p </em>= 0.064). A statistically significant decrease was determined in L-T4 dosages in cases of non-Hashimoto hypothyroidism (<em>p </em>= 0.001). L-T4 requirements decreased in both surgical procedures (<em>p </em>= 0.001)</p><p><strong>Conclusion: </strong>Postoperative L-T4 requirements decrease with weight loss. In addition, no decrease appeared to occur in L-T4 absorption following the surgical procedures in this study.</p> ER -