Author(s): Roberto Negro, Roberto Valcavi, Daniela Agrimi, Konstantinos Toulis
Background: Although replacement treatment with L-thyroxine (LT4) seems easy to manage, about one-third of hypothyroid patients show thyroid-stimulating hormone (TSH) values outside the normal range. Objectives: To explore whether LT4 liquid formulation (monodose vials or drops) affects TSH stability values and to assess its ability to maintain TSH within the normal range compared to tablets.
Methods: A total of 100 hypothyroid patients on replacement treatment with LT4 liquid solution were enrolled (Liquid Group) at a follow-up visit (revisit). The inclusion criteria were 1) treatment for surgical hypothyroidism for at least 2 years or autoimmune hypothyroidism for at least 5 years, 2) normal TSH at the previous visit 12 months before enrollment (baseline visit), and 3) maintenance of the same LT4 dosage during the time interval between the baseline and the follow-up visit. Using the same selection process, we also enrolled 100 hypothyroid patients on replacement treatment with LT4 tablets (Tablet Group).
Results: At the follow-up visit, 19 patients of the Tablet Group and 8 patients of the Liquid Group had abnormal TSH values (P = .023). Weekly and daily LT4 dosage per kilogram were higher in Tablet Group (P = .016 and .006, respectively). The magnitude of TSH change from baseline to follow-up visit was greater in the Tablet Group (P<.001).
Conclusion: The use of LT4 liquid formulation compared to tablet resulted in a significantly higher number of hypothyroid patients who maintained the euthyroid state in a 12-month follow-up period and a reduced variability in TSH values.Journal of Pharmacovigilance