Department of Surgical, Medical and Molecular Pathology and Critical Care, University of Pisa, Pisa, Italy.
Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
Front Endocrinol (Lausanne). 2021 Mar 10;12:633587. doi: 10.3389/fendo.2021.633587. eCollection 2021.
Approximately, 5% of the population is affected by hypothyroidism, mainly women and persons aged more than 60 years. After the diagnosis of hypothyroidism the usual therapy is tablet levothyroxine (L-T4), with a monitoring of the thyroid-stimulating hormone (TSH) level in primary hypothyroidism every 6-8 weeks and L-T4 is adjusted as necessary to reach an euthyroid state. Once TSH is stabilized in the normal range, it is recommended to conduct annual testing in the treated subjects to warrant suitable replacement. More recently advances regarding L-T4 treatment are the introduction of new oral formulations: the liquid solution, and soft gel capsule. The soft gel capsule permits a quick dissolution in the acid gastric pH. The liquid preparation does not require an acid gastric environment. Many pharmacokinetic studies demonstrated a more rapid absorption for the liquid L-T4, or capsule, than with tablet. Many studies have shown that the liquid, or capsule, formulations can overcome the interaction with foods, drugs or malabsorptive conditions, that are able to impair the tablet L-T4 absorption. Lately studies have suggested that liquid L-T4 can permit to maintain more efficiently normal TSH levels in hypothyroid patients in the long-term follow-up, than tablet L-T4, both in patients with malabsorptive states, and in those without malabsorption. Further large, prospective, longitudinal studies are needed to evaluate the stability of TSH, in hypothyroid patients treated with different L-T4 formulations.
大约 5%的人口受到甲状腺功能减退症的影响，主要是女性和 60 岁以上的人群。甲状腺功能减退症确诊后，通常采用左甲状腺素（L-T4）片剂治疗，并在原发性甲状腺功能减退症中每 6-8 周监测一次促甲状腺激素（TSH）水平，必要时调整 L-T4 以达到甲状腺功能正常状态。一旦 TSH 稳定在正常范围内，建议对治疗患者进行年度检测，以确保适当的替代。最近，L-T4 治疗方面的进展是引入了新的口服制剂：液体制剂和软凝胶胶囊。软凝胶胶囊可在酸性胃 pH 值下快速溶解。液体制剂不需要酸性胃环境。许多药代动力学研究表明，与片剂相比，液体 L-T4 或胶囊的吸收更快。许多研究表明，液体或胶囊制剂可以克服与食物、药物或吸收不良状态的相互作用，这些相互作用能够损害片剂 L-T4 的吸收。最近的研究表明，与片剂 L-T4 相比，液体 L-T4 可以更有效地维持甲状腺功能减退症患者长期随访中的正常 TSH 水平，无论是在吸收不良状态的患者还是在没有吸收不良的患者中。需要进一步开展大型、前瞻性、纵向研究，以评估不同 L-T4 制剂治疗的甲状腺功能减退症患者 TSH 的稳定性。
