IN PATIENTS WITH SUBCLINICAL HYPOTHYROIDISM WHILE IN THERAPY WITH TABLET L-T4, THE LIQUID L-T4 FORMULATION IS MORE EFFECTIVE IN RESTORING EUTHYROIDISM

OBJECTIVE: Levothyroxine (L-T4) is the standard therapy of hypothyroidism. Our purpose is to compare the effectiveness of L-T4 liquid formulation, with respect to L-T4 tablet, in hypothyroid patients without malabsorption or drug interference. METHODS: Twentyone subjects with high thyroid-stimulating hormone (TSH) values under therapy with L-T4 tablets were switched to liquid L-T4 at the same dosage, 30 minutes before breakfast. RESULTS: TSH values significantly declined after 2 months from the switch to liquid L-T4, reaching in most cases the normal range. In fifteen (of the twentyone patients) who switched back to tablets, TSH increased again in the hypothyroid range. Since the liquid LT4 formulation resulted in a better control of TSH levels, all patients were finally treated with the liquid L-T4, and TSH, FT3, FT4 were evaluated again after 6 months, and 12 months, resulting in the normal range in all subjects. CONCLUSIONS: The change from tablets to liquid oral formulation normalised serum TSH levels, while switching back to tablets caused thyrotropin levels to worsen. These results suggest that the liquid L-T4 formulation is more effective than tablet one in controlling the TSH levels in hypothyroid patients (in absence of malabsorption, gastric disorders, or drug interference).