Thyrotropin alfa is a manmade form of a protein similar to thyroid-stimulating hormone (TSH), which is normally produced by your thyroid. Thyrotropin alfa keeps your TSH levels steady while you undergo thyroid tests or treatments that can reduce TSH and cause symptoms of low thyroid (hypothyroidism).

Thyrotropin alfa is used together with radioactive iodine ablation (a procedure to remove thyroid tissue that was not removed with surgery) in people with thyroid cancer.

Thyrotropin alfa is also used during medical testing to check for certain types of thyroid cancer that has returned after treatment. Thyrotropin alfa may not help your doctor find all signs of cancer, and there is still a chance that some of your cancer could be missed.

Thyrotropin alfa will not treat cancer that has spread to other parts of the body.

Thyrotropin alfa may also be used for purposes not listed in this medication guide.

You should not use thyrotropin alfa if you are allergic to it.

To make sure thyrotropin alfa is safe for you, tell your doctor if you have ever had:

• kidney disease (or if you are on dialysis);
• heart disease or history of stroke;
• if you take birth control pills; or
• if you are a woman and you smoke or have migraine headaches.

Tell your doctor if you are pregnant, plan to become pregnant or breastfeeding.

Do not use thyrotropin alfa together with radioactive iodine if your are pregnant or breastfeeding.

Use Thyrotropin Alfa (Intramuscular) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

• throat pain or swelling, trouble breathing;
• severe headache;
• severe nausea or vomiting;
• sudden swelling, pain, numbness, or loss of movement in any part of your body;
• signs of overactive thyroid--unexplained weight loss, increased appetite, changes in bowel habits, fast or pounding heartbeats, sweating, feeling anxious or irritable; or
• signs of a stroke--sudden numbness or weakness (especially on one side of the body), sudden headache, slurred speech, problems with vision or balance.

Common side effects may include:

• nausea, vomiting;
• headache, dizziness; or
• weakness, tiredness.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Follow your doctor's instructions about any restrictions on food, beverages, or activity.