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Generation of a Mouse Spontaneous Autoimmune Thyroiditis Model
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Semaglutide therapy and iatrogenic thyrotoxicosis
Maxim John Levy Barnett1, Sarah Eidbo1, Ana Rivadeneira2
1Internal Medicine, Jefferson Einstein Hospital, Philadelphia, Pennsylvania, USA.
Endocrinology, Diabetes & Metabolism Case Reports
|July 10, 2025
Summary
Patients with hypothyroidism on levothyroxine may need dosage adjustments when losing significant weight with obesity medications like semaglutide. This prevents iatrogenic hyperthyroidism caused by over-suppression of thyroid function.
Area of Science:
- Endocrinology
- Pharmacology
Background:
- Levothyroxine is a standard treatment for hypothyroidism.
- Dosage is typically weight-based (1.6 mcg/kg/day for adults).
Observation:
- A patient on stable levothyroxine developed hyperthyroidism after starting semaglutide for obesity.
- Rapid weight loss was associated with palpitations and biochemical evidence of hyperthyroidism.
Findings:
- The patient's levothyroxine dosage became excessive due to weight loss, leading to iatrogenic hyperthyroidism.
- A dosage reduction of levothyroxine was necessary to normalize thyroid function.
Implications:
- Clinicians should monitor thyroid function in hypothyroid patients undergoing weight loss therapy.
- Anticipate potential levothyroxine dosage reductions to prevent iatrogenic hyperthyroidism.
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