Analysis of dose–TSH response effect of levothyroxine soft-gel formulation

• DOI: 10.3389/fendo.2024.1340204
• Publication Date: 2024-02-21T05:22:05Z
• Authors: Pierpaolo Trimboli; Tommaso Piticchio; Zeno Dadda; Ilaria Stramazzo; Elena Gamarra; Lorenzo Ruinelli; Camilla Virili
• Keywords: Levothyroxine

Background Hypothyroidism is treated with daily levothyroxine (LT4). In recent years, soft gel caps of LT4 (LT4-C) have been commercialized, and their performance has optimized. Since guidelines recommend dose according to the tablet preparation efficacy, present study was undertaken obtain data about requirement, normalized per body weight, LT4-C. Methods Patients undergoing LT4-C after total thyroidectomy radioiodine treatment for differentiated thyroid carcinoma were selected. There no specific indication suppression TSH (i.e., <0.5 or <0.1 mIU/L). required maintain a stable during period. interfering factors excluded from this study. Results Thirty patients enrolled (18 females 12 males; median age, 50 years; 71 kg; dose, 1.71 µg/kg/day). The analysis patient age did not reveal any differences. correlated free-T4 p = 0.03), but (p 0.42) free-T3 0.13). <1.0 mIU/L in 90% cases. dose–TSH response effect analysed by probit regression model: probability achieve mIU/l 99% 1.84 (95%CI 1.57–2.12) µg/kg/day, 75% 1.38 µg/kg/day 1.17–1.59), 50% 1.20 0.96–1.43). At ROC curve analysis, most accurate cut-off 1.53 ug/kg/day 70% sensitivity 100% specificity. Conclusions Athyreotic can be initially an lower than previously stated. Therefore, further prospective studies are warranted.