Thyrogen is a manmade form of a protein similar to thyroid-stimulating hormone (TSH), which is normally produced and released into the bloodstream by the pituitary gland. TSH controls production of the thyroid hormones, thyroxine and triiodothyronine, by the thyroid gland by binding to receptors located on cells in the thyroid gland This medicine keeps your TSH levels steady while you undergo thyroid tests or treatments that can reduce TSH and cause symptoms of low thyroid (hypothyroidism).

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

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

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

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

Use only as directed. Tell your doctor if you use other medicines or have other medical conditions or allergies.

Carefully follow your doctor's instructions about the timing of your medications, scans, and other treatments.

Thyrogen is injected into a muscle of the buttock. A healthcare provider will give you this injection.

Thyrogen is usually given in 2 separate injections 24 hours apart.

You may also be given radioactive iodine to take 24 hours after your last Thyrogen injection. If you need a thyroid scan, the scan should take place 48 hours after you take the radioactive iodine.

Carefully follow your doctor's instructions about the timing of your medications, scans, and other treatments.

You may be given steroid medicine to help keep tumors from growing larger while you are receiving Thyrogen.

Your doctor may want you to receive Thyrogen in a hospital or clinic setting to quickly treat any serious side effects that occur.

Drink plenty of liquids before you are treated with Thyrogen.

As part of your treatment, you will need frequent blood tests. You may not notice any change in your symptoms, but your blood work will help your doctor determine whether treatment has been effective.

You should not use Thyrogen if you are allergic to it.

To make sure Thyrogen 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 Thyrogen together with radioactive iodine if your are pregnant or breastfeeding.

Call your doctor for instructions if you miss an appointment for your Thyrogen, or if you will be unable to return for a thyroid scan within 48 hours after you have taken radioactive iodine.

Since Thyrogen is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

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

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

Thyrogen may cause serious side effects. 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 of Thyrogen 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.

Other drugs may affect Thyrogen, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all other medicines you use.