Authors’ Reply to Castello-Bridoux et al.: “Comment on Levothyrox® New and Old Formulations: Are they Switchable for Millions of Patients?”

Authors’ Reply to Lechat et al.: “Levothyrox® New and Old Formulations: Are they Switchable for Millions of Patients?”

“…We are pleased to respond to the letter of Lechat et al [1] as follows. First, as clarified in our response to the letter of Castello-Bridoux et al [2], we now emphasize yet again that the conclusion of our paper [3] clearly distinguished the two possible explanations for a lack of switchability between the new and the old Levothyrox ® formulations. To be clear, these are: (1) a subject-by-patient formulation interaction and (2) a large within-subject variability.…”