Thyroid-stimulating hormone (TSH) suppression therapy

Examples

Generic Name
desiccated thyroid
levothyroxine sodium (Synthroid, Eltroxin)
liothyronine sodium (Cytomel)

These medicines are taken by mouth.

How It Works

Thyroid-stimulating hormone suppression therapy reduces the amount of thyroid-stimulating hormone (TSH) in your body. When you limit the amount of TSH in your body, your thyroid gland stops growing. This may mean that your nodules will also stop growing.

Why It Is Used

When your body makes less TSH, there is less thyroid growth and perhaps less nodule growth. TSH suppression therapy may be used if:

• You have a nodule or nodules that are growing but are not cancerous. TSH suppression therapy may keep them from getting too large.
• You have several nodules (multinodular goiter) and surgery is not a good idea because of other health problems you have. Radioactive iodine can shrink nodules that cause problems with breathing or swallowing, but your nodules may come back after treatment.

How Well It Works

Experts disagree on how well TSH suppression therapy works on non-cancerous (benign) thyroid nodules. Ask your doctor if this treatment is right for you.

Side Effects

TSH suppression therapy can cause many side effects. The side effects usually go away after your doctor has determined the right amount of medicine for you. Side effects can include:

• Diarrhea.
• Weight loss.
• Headache.
• Change in how hungry you feel.
• Sweating a lot.
• Anxiety or irritability.
• Difficulty falling asleep or staying asleep.
• Osteoporosis.
• Arrhythmia.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Experts disagree about the use of TSH suppression therapy for non-cancerous nodules. It is generally not recommended for people who are older than 60 or for post-menopausal women. Talk to your doctor about whether it is right for you.

Your doctor will watch you closely during treatment to make sure you are not receiving too much TSH suppression medicine, which can lead to hyperthyroidism.

Generic versions of levothyroxine are available. The American Association of Clinical Endocrinologists and the Thyroid Society for Education and Research believe that generic levothyroxine is both safe and effective. Talk to your doctor before you switch brands or suddenly stop taking your medicine.

TSH suppression therapy can increase your risk of heart and bone problems, especially if you have heart disease or osteoporosis. If you have heart disease, this kind of medicine can make chest pain or problems with your heart rhythm worse. It can also increase your chances of heart attack. If you have osteoporosis, TSH suppression therapy can further weaken your bones.

Your doctor should stop TSH suppression therapy if your nodule gets larger. A biopsy sample should be done, or surgery should be considered.

Let your doctor know all the medicines you are taking—both prescription medicines and over-the-counter medicines. Some medicines can affect the way thyroid suppression medicines work. You should see your doctor more often to make sure you are taking the correct dose of TSH suppression medicine if:

• You are taking cholestyramine, ferrous sulfate (iron), sucralfate, and some antacids that contain aluminum hydroxide. These can interfere with how levothyroxine is absorbed.
• You are taking seizure medicines (anticonvulsants).
• You are taking a medicine that is used to treat tuberculosis (rifampin).

If you are pregnant or if you take estrogen (estrogen replacement therapy, or ERT), hormone replacement therapy (HRT), or birth control pills (oral contraceptives), you may need to increase your dose of TSH suppression medicine. If you have recently stopped taking ERT, HRT, or birth control pills, you may need to decrease your dose of TSH suppression medicine. You may also need to decrease your dose of TSH suppression medicine after childbirth. Talk to your doctor about the right amount of medicine for you.

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Author:	Caroline Rea, RN, BS, MS	Last Updated: July 13, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine Matthew I. Kim, MD - Endocrinology & Metabolism Anne C. Poinier, MD - Internal Medicine
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