Thyroid medications include many different options that differ not only in composition, but also in purpose. Hormone replacement therapy like Synthroid (levothyroxine) is the most widely used medication for hypothyroidism . An antithyroid drug such as tapol (methimazole) can be used for hyperthyroidism , and patients with thyroid cancer may require radioactive iodine therapy or chemotherapy.
However, they all have one thing in common: treatment with them must be optimized to properly treat your thyroid condition.
Medications for hypothyroidism
The function of the thyroid gland is to produce the hormones thyroxine (T4) and triiodothyronine (T3). These thyroid hormones regulate everything from heart rate and body temperature to respiratory function and a woman's menstrual cycle.
When the thyroid gland becomes insufficient, due to Hashimoto's disease (an autoimmune disease), iodine deficiency, or surgical removal of the thyroid , among other reasons, insufficient amounts of thyroid hormone are produced, resulting in a variety of symptoms that affect one or more organ systems and their severity ranges from mild to debilitating .
To restore proper thyroid hormone levels in the body, all people with hypothyroidism should take thyroid hormone replacement medications, except those whose underactive thyroid is transient (such as thyroiditis) or reversible (such as that caused by a medication that may suspend).
There are four main goals of thyroid hormone replacement therapy:
- Relieve symptoms of hypothyroidism
- Normalize thyroid stimulating hormone (TSH) levels
- Reduce the size of an enlarged thyroid gland (goiter), if applicable.
- Avoid excessive medication (hyperthyroidism )
Levothyroxine , also called l-thyroxine and L-T4, is synthetic form of the hormone T4 (thyroxine). T4 is a storage hormone and must be converted to T3, an active hormone for cells to use.
Levothyroxine is the drug of choice for the treatment of hypothyroidism. In the United States, Synthroid , Levoxyl , Unithroid , and Tirosint are trademarks.
Liothyronine synthetic form T3 (triiodothyronine). The brand names for liothyronine in the United States are Cytome l and Triostat .
Because experts generally recommend T4 monotherapy rather than T4 / T3 combination therapy for hypothyroidism, this drug is generally not prescribed .
It is being investigated whether T4 / T3 combination therapy can benefit a subset of people with hypothyroidism who have a specific gene mutation. It is very important to be aware of this research as it may change your thyroid treatment in the future.
Natural desiccated thyroid gland
Natural Dehydrated Thyroid , also known as NDT, Natural Thyroid, or Pig Thyroid, is a prescription drug obtained from the dried thyroid gland of pigs. NDT contains both T4 and T3.
Common brand names are Armor Thyroid and Nature-throid , and a generic drug is also available.
Most endocrinologists and many health professionals do not endorse or prescribe the use of natural dehydrated thyroid medications; this is because they are combination drugs and the ratio of T4 to T3 does not match the ratio of T4 to T3 in humans. However, a few selected patients may respond well to nondestructive testing.
Medications for hyperthyroidism
Hyperthyroidism means that the thyroid gland is overactive and produces too much thyroid hormone. There are several causes of hyperthyroidism , including Graves disease (another type of autoimmune disease), benign thyroid nodules , inflammation of the thyroid gland ( thyroiditis ), and a malfunctioning pituitary gland (which works in conjunction with the thyroid gland ). Furthermore, the Hashimoto phase of disease can also cause hyperthyroidism in the same way as hypothyroidism.
Treatment of hyperthyroidism is usually more difficult than hypothyroidism and requires one or more of the following treatments:
- Antitroid drug
- Radioactive iodine (RAI)
- Surgery to remove the gland (thyroidectomy)
The only "cures" for hyperthyroidism are antithyroid drugs. There are currently two drugs approved in the United States for the treatment of hyperthyroidism.
- Tapazole (methimazole or MMI)
- Propylthiouracil (PTU)
The antithyroid drug Tapazol prevents the thyroid gland from using iodine, usually from food, to make thyroid hormone. This is a drug that patients usually take once a day. Tapazol has fewer side effects and resolves hyperthyroidism faster than PTU, making it the antithyroid drug of choice .
PTU suppresses the formation of the thyroid gland with the help of iodine, which slows down the overproduction of thyroid hormone. It also inhibits the conversion of the thyroid hormone T4 to T3. PTU has a short-lived action, so patients taking this drug are often advised to take the drug two or three times a day to effectively lower thyroid hormone levels.
PTU has more side effects than the other drugs discussed here. It is the drug of choice for hyperthyroidism only in certain situations: early in pregnancy, severe thyroid disease, and in case the patient experiences serious side effects from methimazole .
Beta-blockers such as Inderal (propranolol) are not used to "treat" hyperthyroidism, but to reduce symptoms of excess thyroid hormone in the body, such as increased heart rate, tremors, and anxiety.
Thyroid Cancer Medications
The main treatment for most thyroid cancers is surgery to remove the entire thyroid gland (total thyroidectomy) or the lobe of the thyroid gland (lobectomy) .
After surgery, patients will need thyroid hormone replacement drugs (levothyroxine) to replenish thyroid hormone production and suppress tumor regrowth.
Levothyroxine is used to treat hypothyroidism due to thyroid surgery for cancer, just as it is used for other cases of underactive thyroid gland. Depending on the degree of the disease and the risk of thyroid cancer recurrence in a person, the doctor will determine in what range the TSH should be suppressed and will adjust the levothyroxine level accordingly.
TSH suppression is important to prevent the cancer from coming back.
Radioactive iodine therapy
If you have large thyroid cancer, thyroid cancer that has spread to the lymph nodes, and / or if you think you are at high risk of cancer recurrence, you may be prescribed radioactive iodine therapy after surgery .
Radioactive iodine is given in a hospital, either in liquid or capsule form. Its main goal is to kill cancer cells that are left from the surgery and destroy the remaining thyroid tissue.
Chemotherapy that kills rapidly dividing cells, such as cancer cells, is not often used to treat thyroid cancer, unless the person has recurrent or metastatic cancer . Chemotherapy is also combined with external beam radiation to treat a rare type of thyroid cancer called anaplastic thyroid cancer .
Scientists have developed several drugs called "targeted therapies" that target specific markers on cancer cells. Some of these drugs have been used to treat advanced or persistent thyroid cancer.
Nexavar (sorafenib) and Lenvima (lenvatinib) are two targeted treatments , kinase inhibitors, that work in part by blocking the growth of thyroid cancer and the formation of new blood vessels .
Get the word of drug information
Sure, the diagnosis of "thyroid disease" can be overwhelming. But when you learn about the medications used to treat your condition, you are already taking the first step in your treatment.
Remember, as you continue your journey to the thyroid gland, you are not alone, and for most of you, your condition can be cured or well controlled. Feel free to tell your doctor how you feel. In many cases, the patient can benefit from an adjusted dose or even a change in drug.
Thyroid Discussion Guide for Healthcare Professionals
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