Should I Use Antithyroid Medication or Radioactive Iodine to Treat Hyperthyroidism?

Introduction

This information will help you understand your choices, whether you share in the decision-making process or rely on your doctor's recommendation.

Key points in making your decision

Graves' disease is the most common cause of hyperthyroidism. If your hyperthyroidism is not caused by Graves' disease, this information may not apply to you.

Consider the following when making your decision:

Most people will be cured of hyperthyroidism after one dose of radioactive iodine. The radioactivity in the iodine destroys most or all of the tissue in your thyroid gland. This may lead to hypothyroidism, which means your body makes too little thyroid hormone. If you develop hypothyroidism, you have to take thyroid hormone medication for the rest of your life.
If you are pregnant, want to become pregnant within 6 months of treatment, or are breast-feeding, you cannot use radioactive iodine.
You can use radioactive iodine therapy after you have been treated with antithyroid medication.
Radioactive iodine is often recommended if you have Graves' disease and are older than 50, or if you have thyroid nodules (toxic multinodular goiter) that are releasing too much thyroid hormone.
Antithyroid medication works best if you have mild hyperthyroidism, if this is the first time you are being treated for Graves' disease, if you are younger than 50, or if your thyroid gland is only swollen a little bit (small goiter).
Antithyroid medication does not damage your thyroid gland. But it doesn't work for everyone, and you may have a relapse.
If you have used antithyroid medication and you have a relapse, taking antithyroid medication again may not work.

Medical Information

What is hyperthyroidism?

Hyperthyroidism develops when the thyroid gland makes too much thyroid hormone. Thyroid hormones control your metabolism—how your body turns food into energy—and influence your heart rate, digestion, muscle and bone strength, and cholesterol levels. When you have too much thyroid hormone, all of your body's functions speed up.

What are the risks of hyperthyroidism?

If you do not get treatment, hyperthyroidism can lead to heart problems, bone problems, and thyroid storm, a life-threatening condition that occurs when the thyroid releases a lot of thyroid hormone in a short period of time.

For more information, see the topic Hyperthyroidism.

Your Information

Your choices are:

Try radioactive iodine, which destroys part or all of the tissue in the thyroid gland.
Try antithyroid medication, which decreases the amount of thyroid hormone in your body.

Doctors rarely treat hyperthyroidism with surgery to remove part or all of the thyroid gland (thyroidectomy).

The decision about whether to use antithyroid medication or radioactive iodine takes into account your personal feelings and the medical facts.

**Deciding about antithyroid medication**
Reasons to use antithyroid medication	Reasons not to use antithyroid medication
Remission rates up to 50% have been reported.¹ You have mild hyperthyroidism. This is the first time you are being treated for hyperthyroidism. You are younger than 50. Antithyroid medication does not cause permanent thyroid damage. If the medication does not work, you can use radioactive iodine. Your symptoms will start to go away in 1 to 8 weeks. It may reduce your risk of developing Graves' opthalmopathy. Are there other reasons you might want to use antithyroid medication?	You need to take the medication at the same time every day. You need to take the medication for 1 to 2 years, and the hyperthyroidism may return. You have already used antithyroid medication, and your hyperthyroidism has returned. Remission rates vary, and relapses are common. There is no good way to know who will have remission. Side effects include rash, itching, joint aches, liver problems, and a decreased ability to fight infection because of a low white blood cell count. Are there other reasons you might not want to use antithyroid medication?

**Deciding about radioactive iodine**
Reasons to use radioactive iodine	Reasons not to use radioactive iodine
Most people are cured after one dose of radioactive iodine. Long-term antithyroid drug therapy has not worked. You cannot use antithyroid medication because of side effects. Are there other reasons you might want to use radioactive iodine?	Side effects include an inflamed thyroid gland shortly after treatment. Hypothyroidism usually develops within 1 to 10 years.¹ You may need to take more than one treatment. You are younger than 20. It takes 8 to 24 weeks for symptoms to start to go away. It may make Graves' ophthalmopathy worse for a while. You are pregnant, want to become pregnant within 6 months of treatment, or are breast-feeding. Are there other reasons you might not want to use radioactive iodine?

These personal stories may help you make your decision.

Wise Health Decision

Use this worksheet to help you make your decision. After completing it, you should have a better idea of how you feel about using antithyroid medication or radioactive iodine. Discuss the worksheet with your doctor.

Circle the answer that best applies to you.

My hyperthyroidism is caused by Graves' disease.	Yes	No	Unsure
I worry about getting hypothyroidism after treatment with radioactive iodine.	Yes	No	Unsure
I have a hard time remembering to take medication.	Yes	No	Unsure
I understand that results vary for those taking antithyroid medication.	Yes	No	Unsure
This is the first time I am being treated for hyperthyroidism.	Yes	No	Unsure
I am pregnant or breast-feeding.	Yes	No	NA*
I want to become pregnant within 6 months of being treated.	Yes	No	NA
I have already tried antithyroid medicine, without good results.	Yes	No	NA

*NA = Not applicable

Use the following space to list any other important concerns you have about this decision.

What is your overall impression?

Your answers in the above worksheet are meant to give you a general idea of where you stand on this decision. You may have one overriding reason to use or not use antithyroid medication or radioactive iodine to treat hyperthyroidism.

Check the box below that represents your overall impression about your decision.

Leaning toward antithyroid medication

Leaning toward radioactive iodine

Return to the topic Hyperthyroidism.

References

Citations
Jameson JL, Weetman AP (2005). Disorders of the thyroid gland. In DL Kasper et al., eds., Harrison's Principles of Internal Medicine, 16th ed., vol. 2, pp. 2104–2127. New York: McGraw-Hill.

Credits

Author	Caroline Rea, RN, BS, MS
Editor	Maria G. Essig, MS, ELS
Associate Editor	Pat Truman, MATC
Primary Medical Reviewer	Caroline S. Rhoads, MD - Internal Medicine
Specialist Medical Reviewer	David C.W. Lau, MD, PhD, FRCPC - Endocrinology & Metabolism
Last Updated	December 3, 2007

Author:	Caroline Rea, RN, BS, MS	Last Updated: December 3, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine David C.W. Lau, MD, PhD, FRCPC - Endocrinology & Metabolism
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