How Hyperthyroidism Is Treated

A Look at Antithyroid Drugs, Radioactive Iodine, and Surgery

The best treatment for your hyperthyroidism depends on several factors, from the cause of your issue to your age, the severity of your case to your overall health. While antithyroid drugs (Tapazole, for example) can be used to help the thyroid function normally, other treatments—such as beta-blockers—may be considered to ease hyperthyroid symptoms.

Options such as ablation of the thyroid with radioactive iodine or surgery to remove the gland (thyroidectomy) may also be considered.

While all three options are effective, they each have varying costs and potential side effects. This is why a careful and thorough discussion with your doctor is warranted before devising a treatment plan.

Prescriptions

Prescription medications are typically the main treatment for hyperthyroidism. You may also be prescribed other drugs to help you manage related symptoms.

Antithyroid Drug Treatment

The goal of antithyroid drugs is to achieve normal thyroid function within a month or two of beginning treatment. Then a person may proceed with the following options:

  • Undergo definitive therapy with radioactive iodine or surgery
  • Continue the antithyroid drug for another year or two, with the hope of achieving remission (which is most likely in people with mild hyperthyroidism and less likely in people with a large goiter and those who smoke)
  • Take an antithyroid drug long-term

While long-term antithyroid drug treatment is appealing (you have a chance of remission, treatment is reversible, and you can avoid the risks and expenses associated with surgery), the downside is that researchers estimate up to 70 percent of people will relapse after the antithyroid drug treatment is stopped.

The two antithyroid drugs available in the United States are Tapazole (methimazole, or MMI) and propylthiouracil (PTU). Due to the fact that MMI has fewer side effects and reverses hyperthyroidism more rapidly than PTU, MMI is the preferred choice.

That said, PTU is used to treat hyperthyroidism during the first trimester of pregnancy and in people who are experiencing a thyroid storm. It may also be given to people who have had a reaction to methimazole and who do not want to undergo radioactive iodine or surgery.

Some possible minor side effects associated with taking either MMI or PTU include:

  • Itching
  • Rash
  • Joint pain and swelling
  • Nausea
  • Fever
  • Changes in taste

More seriously, liver injury with either MMI or PTU (more common with the latter) may occur. Symptoms of liver injury include abdominal pain, jaundice, dark urine, or clay-colored stools. While uncommon, a potentially life-threatening condition called agranulocytosis (a lowering of the infection-fighting cells in your body) may occur with either MMI or PTU. It's essential for people taking these drugs to notify their doctor right away if they develop symptoms of an infection like a fever or a sore throat. 

Beta Blocker Therapy

While it's not a treatment for hyperthyroidism, many people with hyperthyroidism are prescribed a beta-adrenergic receptor antagonist (known more commonly as a beta-blocker).

A beta-blocker works in the body to alleviate the effects of excess thyroid hormone on the heart and circulation, especially rapid heart rate, blood pressure, palpitations, tremor, and irregular rhythms. Beta blockers also reduce the breathing rate, reduce excessive sweating and heat intolerance, and generally reduce feelings of nervousness and anxiety.

Drugs for Thyroiditis

For the temporary or "self-limited" forms of hyperthyroidism (for example, subacute thyroiditis or postpartum thyroiditis), the focus is primarily on treating the symptoms. Pain relievers may be given for thyroid pain and inflammation, or beta blockers may be prescribed for heart-related symptoms.

Occasionally, an antithyroid drug is prescribed for a short time.

Ablation

Radioactive iodine (RAI) is used to destroy the tissues of the thyroid gland, what's known as ablation. It is used to treat the majority of people diagnosed with Graves' disease in the United States, but it cannot be used in women who are pregnant or breastfeeding, or people with thyroid cancer in addition to their hyperthyroidism.

During RAI therapy, radioactive iodine is given as a single dose, in a capsule or by an oral solution. After a person has ingested the RAI, the iodine targets and enters the thyroid, where it radiates the thyroid cells, damaging and killing them. As a result, the thyroid gland shrinks and thyroid function slows down, reversing a person's hyperthyroidism.

This usually occurs within six to 18 weeks after ingesting the radioactive iodine, although some people require a second RAI treatment. 

In people who are older, who have underlying health conditions like heart disease, or who have significant symptoms of hyperthyroidism, an antithyroid drug (methimazole, typically) is used to normalize thyroid function before undergoing RAI therapy. Methimazole is also given about three to seven days after RAI therapy in these individuals, then gradually tapered as their thyroid function normalizes.

Side Effects and Concerns

RAI can have some side effects, including nausea, sore throat, and swelling of the saliva glands, but these are usually temporary. A very small percentage of patients are at risk of life-threatening thyroid storm after RAI. 

Moreover, there is scientific evidence showing that RAI therapy may lead to the development or worsening of Graves' eye disease (orbitopathy). While this worsening is often mild and short-lived, the American Thyroid Association guidelines do not recommend giving RAI therapy to people with moderate to severe eye disease.

If you have RAI, your doctor will discuss the radiation level and any precautions you might need to take to protect your family or the public. That said, be at ease that the amount of radiation used in RAI therapy is small and does not cause cancer, infertility, or birth defects. 

Generally, however, in the first 24 hours after RAI, avoid intimate contact and kissing. In the first five days or so after RAI, limit exposure to young children and pregnant women, and, in particular, avoid carrying children in a way that they will be exposed to your thyroid area. 

Surgery

Thyroid surgery (known as thyroidectomy) is generally a last choice option for treating an overactive thyroid gland. While removing the thyroid gland is very effective for treating hyperthyroidism, surgery is invasive, costly, and somewhat risky.

Overall, surgery is recommended in the following situations:

  • If antithyroid drugs and/or RAI have been unable to control the condition 
  • If a person is allergic to antithyroid drugs and does not want RAI therapy
  • If a person has a suspicious, possibly cancerous thyroid nodule 
  • If a person has a very large goiter (especially if it's blocking the airway or making it difficult to swallow), severe symptoms, or active Graves' eye disease

When undergoing thyroid surgery, your doctor will decide whether to remove the entire thyroid gland (called a total thyroidectomy) or part of the gland (called a partial thyroidectomy). This decision is not always an easy one and requires a thoughtful discussion and evaluation.

Generally speaking, which type of surgery you undergo depends on the cause of your hyperthyroidism. For instance, a single nodule overproducing thyroid hormone located on the left side of your thyroid gland may be treated with a partial thyroidectomy (the left side of the thyroid gland is removed).  On the other hand, a large goiter that takes up both sides of the thyroid may be treated with a total thyroidectomy. 

Post-Surgical Management and Risks

If you undergo a total thyroidectomy, lifelong thyroid hormone replacement is required. On the other hand, with a partial thyroidectomy, there is a good chance that you will not require permanent thyroid medication, as long as there is enough gland left to produce an adequate amount of thyroid hormone. 

As with any surgery, it's important to review potential risks with your doctor. For thyroid surgery, the possible risks include bleeding, and damage to the recurrent laryngeal nerve (causing hoarseness) and/or the parathyroid gland (which regulates calcium balance in the body). With an experienced thyroid surgeon, though, these risks are small. 

During Pregnancy

It's generally advised that if a woman is hyperthyroid and desires pregnancy in the near future that she consider RAI therapy or surgery six months prior to becoming pregnant.

Pregnant women with symptoms and/or moderate-to-severe hyperthyroidism require treatment. The recommended therapy is an antithyroid drug, starting with PTU in the first trimester and then switching to methimazole in the second and third trimesters (or staying on PTU). 

While these drugs do carry risk in pregnant women, your doctor’s mission is to use them as minimally as possible to control the hyperthyroidism and reduce the risks it poses to you and your baby.

Typically, doctors recommend the smallest possible dose that will control the condition. Since all antithyroid drugs do cross the placenta, however, it’s especially important to follow prescription instructions and keep up with recommended check-ups (occurring every two to four weeks).

At healthcare visits, in addition to thyroid testing, your pulse, weight gain, and thyroid size will be checked. Pulse should remain below 100 beats per minute. You should strive to keep your weight gain within the normal ranges for pregnancy, so speak with your doctor about proper nutrition and what types of physical activity are appropriate for your current condition. Fetal growth and pulse should also be monitored monthly.

In Children

As in adults, hyperthyroidism in children may be treated with antithyroid drug therapy, radioactive iodine, or thyroidectomy. 

The treatment of choice in children with hyperthyroidism is the antithyroid drug MMI, as it carries the least risks compared to RAI or surgery, and it has fewer side effects compared to PTU. While RAI or surgery or acceptable alternative therapies, RAI is avoided in children under age 5.

Complementary Medicine (CAM)

In China and other countries, Chinese herbs are sometimes used to treat hyperthyroidism, either alone or together with an antithyroid drug. While the precise mechanism is unclear, some believe the herbs work by preventing the conversion of thyroxine (T4) to triiodothyronine (T3) and by lowering the effects of T4 on the body. 

In a large review study, which examined thirteen trials of over 1700 people with hyperthyroidism, the addition of Chinese herbs to antithyroid drugs was effective in improving symptoms and reducing both side effects of the antithyroid drugs and relapse rates (meaning a recurrence of the hyperthyroidism) in some people. The authors of the study, however, noted that all of these trials were not well-designed. Due to their low quality, the authors state that there is not strong enough evidence to support implementing Chinese herbal medicines in the treatment of hyperthyroidism. 

Since Chinese herbs (or other alternative therapies) could affect your medication and thyroid levels negatively, it's important to only take them under the guidance of your endocrinologist. 

Besides Chinese herbs, vitamin D has received a lot of attention within the thyroid community. While a link has been found between vitamin D deficiency and autoimmune thyroid disease (both Graves' disease and Hashimoto's disease), it's still unclear what this association means, like whether vitamin D deficiency is a trigger or consequence of thyroid dysfunction. 

We do know that hyperthyroidism may contribute to bone weakening (osteoporosis), so ensuring proper vitamin D and calcium intake is critical. The Institute of Medicine recommends 600 international units (IUs) of vitamin D a day for adults ages 19 to 70 and 800 IUs for adults over age 70. That said, it's still a good idea to confirm your vitamin D dose with your doctor. He may recommend checking your vitamin D level with a blood test; if you are deficient, you may require higher doses than these recommendations indicate. 

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