What are the considerations for using Ozempic (semaglutide) in patients with hyperthyroidism?

Ozempic (Semaglutide) and Hyperthyroidism

Critical Contraindication and Safety Concern

Ozempic is absolutely contraindicated in patients with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), but hyperthyroidism itself is not a contraindication to semaglutide use. 1

Understanding the Thyroid-Related Concerns

The primary thyroid concern with semaglutide relates to thyroid C-cell tumors, not hyperthyroidism:

• In rodent studies, semaglutide causes dose-dependent and treatment-duration-dependent thyroid C-cell tumors at clinically relevant exposures, though human relevance has not been determined 1
• This carries an FDA Black Box Warning regarding the risk of thyroid C-cell tumors, specifically medullary thyroid carcinoma 1
• GLP-1 receptors are expressed in the thyroid gland, which may explain some pleiotropic effects of semaglutide 2

Pre-Treatment Screening Requirements

Before initiating semaglutide, you must screen for:

• Personal history of medullary thyroid carcinoma or thyroid C-cell tumors 1
• Family history of medullary thyroid carcinoma 1
• Multiple Endocrine Neoplasia syndrome type 2 (MEN 2) 1
• Current thyroid function status (TSH, T3, T4) 3

However, routine monitoring of serum calcitonin or thyroid ultrasound is of uncertain value for early detection of MTC in patients treated with semaglutide 1

Special Consideration: Hyperthyroidism Management

If you have a patient with pre-existing hyperthyroidism, semaglutide can be used, but requires specific monitoring:

• For patients on levothyroxine who lose significant weight with semaglutide, anticipate the need for levothyroxine dose reduction to prevent iatrogenic hyperthyroidism 4
• Weight loss can lead to over-suppression of thyroid function in patients on stable levothyroxine doses, as the medication becomes supratherapeutic relative to the new lower body weight 4
• Monitor for clinical and biochemical evidence of hyperthyroidism (palpitations, tremor, elevated free T4, suppressed TSH) during treatment 4

Practical Clinical Algorithm

For patients with hyperthyroidism considering semaglutide:

1. Ensure hyperthyroidism is well-controlled before initiating semaglutide 5
2. Screen for absolute contraindications: personal/family history of MTC or MEN 2 1
3. Obtain baseline thyroid function tests (TSH, free T4, free T3) 3
4. If on levothyroxine for hypothyroidism, monitor thyroid function every 3 months during active weight loss phase 4
5. Counsel patients about symptoms of thyroid tumors: neck mass, dysphagia, dyspnea, persistent hoarseness 1

Common Pitfall to Avoid

The most critical error is confusing hyperthyroidism with the medullary thyroid carcinoma risk. Hyperthyroidism (overactive thyroid) is NOT a contraindication to semaglutide use. The contraindication is specifically for medullary thyroid carcinoma or MEN 2 1. Many clinicians inappropriately withhold semaglutide from patients with hyperthyroidism due to this confusion.

Monitoring During Treatment

• No routine calcitonin monitoring is recommended unless clinically indicated 1
• Monitor thyroid function if patient is on thyroid replacement therapy and experiencing significant weight loss 4
• Watch for symptoms suggesting thyroid tumors, though these are rare 1