Resistance to levothyroxine in a bariatric surgery patient: an indication for liquid formulation?

We report the case of a 49-year-old female patient with hypothyroidism who underwent bariatric surgery and developed severe hypothyroidism despite high doses of oral levothyroxine (L-T4) tablets. Initially, a high-dose L-T4 tablets absorption test was performed to exclude pseudo-malabsorption. In view of a modest increase in serum T4 levels, L-T4 liquid formulation absorption test was performed, and showed faster and more efficient absorption of thyroid hormones. We discuss the issue of distinguishing malabsorption from pseudo-malabsorption, review the literature concerning the benefits of liquid L-T4 in cases of impaired absorption such as bariatric surgery and consider the socio-economic implications of different liquid formulations.