Can a patient with hyperthyroidism take Ozempic (semaglutide)?

Can Patients with Hyperthyroidism Take Ozempic (Semaglutide)?

Yes, hyperthyroidism is not a contraindication to semaglutide use, but the absolute contraindication is a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia syndrome type 2 (MEN2), not hyperthyroidism itself. 1, 2

Absolute Contraindications Related to Thyroid

• Semaglutide carries an FDA Black Box Warning regarding thyroid C-cell tumors based on rodent studies, making it absolutely contraindicated in patients with personal or family history of medullary thyroid cancer or MEN2. 1, 2, 3
• This contraindication applies to all formulations of semaglutide (Ozempic, Wegovy, Rybelsus) and is based on animal studies showing thyroid C-cell tumor development. 1, 3

Hyperthyroidism Is NOT a Contraindication

• Hyperthyroidism itself does not appear on any contraindication list for semaglutide across multiple guideline societies including the American College of Cardiology, American Diabetes Association, and Endocrine Society. 1, 2
• The thyroid-related concern with semaglutide is specifically about medullary thyroid cancer risk, not thyroid function disorders like hyperthyroidism or hypothyroidism. 1, 3

Critical Pre-Treatment Screening Required

• Before initiating semaglutide, you must screen for personal or family history of medullary thyroid cancer or MEN2 syndrome—this is non-negotiable. 1, 4
• Baseline thyroid function tests (TSH, T3, T4) should be obtained, though current practice shows these are monitored in most patients while calcitonin levels (which would detect medullary thyroid cancer) are rarely checked. 4
• A retrospective study of 715 patients found that only 1.8% had adequate disease history assessment performed despite 98.6% having at least one relevant condition, highlighting a critical gap in pre-treatment evaluation. 4

Special Monitoring Considerations for Hyperthyroid Patients

• Hypothyroidism events (all grade 1 or 2) occur in approximately 8.1% of patients on GLP-1 agonists, but this represents development of hypothyroidism, not worsening of existing hyperthyroidism. 1
• GLP-1 receptors are expressed in the thyroid gland, which may explain some pleiotropic effects, but this does not translate to contraindication in hyperthyroidism. 1
• The Endocrine Society recommends monitoring thyroid function during therapy, particularly relevant if the patient is being treated for hyperthyroidism concurrently. 1

Important Clinical Caveat for Weight Loss

• If your hyperthyroid patient is also on levothyroxine replacement (post-treatment hypothyroidism), significant weight loss from semaglutide may require levothyroxine dose reduction to prevent iatrogenic hyperthyroidism. 5
• A case report documented a patient on stable levothyroxine who developed iatrogenic thyrotoxicosis after rapid weight loss on semaglutide, requiring dosage reduction based on the new lower body weight (approximately 1.6 mcg/kg). 5
• The mechanism is believed to involve either increased medication absorption or the weight loss itself creating a supratherapeutic levothyroxine level. 5

Algorithm for Decision-Making

1. Screen for absolute contraindications: Personal or family history of MTC or MEN2? If YES → Do not prescribe semaglutide. 1, 2

2. If hyperthyroidism is the only thyroid condition: Proceed with semaglutide if otherwise indicated (BMI ≥30 or ≥27 with comorbidities). 1, 2

3. Obtain baseline labs: TSH, T3, T4 at minimum; consider calcitonin if any thyroid nodules or family history concerns exist. 4

4. If patient is on thyroid medication: Plan for potential dose adjustments as weight loss occurs, with monitoring every 3 months initially. 5

5. Monitor thyroid function: Check TSH every 3-6 months during active weight loss phase, more frequently if on thyroid replacement therapy. 1, 5

Common Pitfalls to Avoid

• Do not confuse hyperthyroidism with the medullary thyroid cancer contraindication—these are entirely different conditions with different implications for semaglutide use. 1, 3
• Do not fail to ask specifically about family history of medullary thyroid cancer or MEN2, as this is the critical screening question. 1, 4
• Do not assume stable thyroid medication doses will remain appropriate during significant weight loss—anticipate need for adjustment. 5
• Do not order calcitonin levels routinely unless there are specific concerns (thyroid nodules, family history), as this is not standard practice and was not performed in any patients in a large retrospective study. 4