Endocrine Abstracts

Levothyroxine (l-T₄) is the mainstay of treating hypothyroidism. Despite the ‘classic’ tablet formulation of l-T₄, pharmaceutical industries have recently introduced other formulations such as liquid and a soft gel capsule in a few countries. Recent studies have shown a better absorption of these formulations compared with the traditional tablet bypassing the pH-depending dissolution phase and less suffering the binding by sequestrants in the intestinal lumen. Our preliminary data of the ‘TICO’ study, a double-blind, placebo-controlled trial aimed to evaluate the efficacy of oral liquid l-T₄ assumed at breakfast, seems to demonstrate that oral liquid thyroxine makes no difference to the thyroid hormonal profile (TSH, fT₄ and fT₃) regardless assumed before or during breakfast. Based on these preliminary data, we have conducted the ‘TITI’ (Tirosint^® vs Tiche^®, Ibsa farmaceutici Italia) study in order to verify the thyroid hormonal profile of patients assuming l-T₄ in soft gel capsule during breakfast. We have enrolled 30 (25/5 female/male, 47.1±11.9 years old) euthyroid patients on stable liquid l-T₄ therapy assumed during breakfast. According to the study design all patients switched the liquid formulation to soft gel capsule maintaining the same dosage and the usual breakfast. After 6 weeks TSH, fT₄ and fT₃ values were re-tested. At the end of the study no differences to TSH serum (2.61±1.44 vs 2.23±1.16 mlU/l, P=0.269), fT₄ (10.43±1.25 vs 9.91±1.26 pg/ml, P=0.120) and fT₃ (2.71±0.39 vs 2.88±0.31 pg/ml, P=0.068) were observed among the patients whether assuming liquid or soft gel capsule at breakfast. In conclusion, we have clearly demonstrated that l-T₄ soft gel capsule can be taken at breakfast without difference from liquid formulation, facilitating compliance to l-T₄ replacement therapy.