Semaglutide therapy and iatrogenic thyrotoxicosis
Summary Levothyroxine is the backbone of hypothyroidism treatment. The dosage of levothyroxine varies; however, as an estimate, an average adult patient will require 1.6 micrograms per kilogram of body weight. We present the case of a patient with hypothyroidism, controlled on a stable dosage of levothyroxine, who subsequently began semaglutide therapy for obesity. She developed rapid weight loss and presented with palpitations as her main symptoms. Both clinical and biochemical analyses demonstrated new hyperthyroidism. With the weight loss, it was deemed that her levothyroxine dosage was no longer appropriate for her new weight and was over-suppressing her thyroid function (iatrogenic hyperthyroidism), requiring a dosage reduction. With follow-up, both clinical assessment and biochemical studies noted a reduction in the suppression of the thyroid axis. This case highlights the importance of considering a dosage reduction of levothyroxine when patients lose significant weight (such as
