Medications for Thyroid Disease

Several medications can be used to treat thyroid disease. These will depend on the type of pathology, its extension and the specific condition of each patient.
Medications for Thyroid Disease
Samuel Antonio Sánchez Amador

Written and verified by el biólogo Samuel Antonio Sánchez Amador in 24 July, 2021.

Last update: 24 July, 2021

The thyroid is a butterfly-shaped gland located in the neck. It’s an endocrine tissue conglomerate, and is responsible for secreting hormones that are essential for the functioning of the body. If this structure fails, medications for thyroid disease may be needed.

Here’s a list of medications that alleviate the clinical signs of various thyroid diseases. Each disorder has a special approach.

Goiter

Goiter is an abnormal enlargement of the thyroid gland. Although it’s a painless condition, it can cause coughing and make swallowing difficult. As the Mayo Clinic indicates, the most common cause worldwide is a lack of iodine in the diet.

Levothyroxine sodium

Levothyroxine is a synthetic form of thyroxine (thyroid hormone) that is used as a hormone replacement in patients with thyroid problems. Each tablet contains 50 micrograms of the active ingredient and you consume it in the morning on an empty stomach —30 to 60 minutes before eating.

As indicated by the Elsevier portal, this drug can reduce the size of goiters by 25%, as long as it’s administered during the first months of the evolution of the condition. In addition, its use is only conceived when the goiter is the result of hypothyroidism, as its main effect is to inhibit thyrotropin or TSH.

Levothyroxine is found under the trade names Levoxyl ®, Synthroid ® and Tirosint ®, among others.

Corticosteroids

When the goiter is severe and the patient is unable to swallow or carry out normal vital functions, corticosteroids are prescribed, the function of which is to reduce inflammation by suppressing the immune system. The usual dose of corticosteroids is 80 to 100 milligrams per day of prednisone.

Radioiodine

As indicated by the Medigraphic portal, radioactive iodine 131 therapy is useful for patients with autoimmune hyperthyroidism and the product of a multinodular goiter or toxic adenoma. We’ll now delve more into the particularities of this approach in the next few lines.

Goiter in a patient who needs thyroid medication.
Goiter is the enlargement of the thyroid gland, which can put pressure on the structures of the neck.

Hyperthyroidism

Hyperthyroidism is a thyroid disease that occurs when the gland produces more hormones than the body needs. Causes are Graves’ disease, thyroid nodules, thyroiditis, too much iodine in the diet, or too much medication for an underactive thyroid. The prevalence ranges between 0.3 and 1% of the general population.

Antithyroid drugs

The function of antithyroid drugs is to decrease the two hormones produced by the thyroid: thyroxine (T4) and triiodothyronine (T3). They can be used both in the short and long term, although they report certain side effects that should be taken into account.

Within this group, the two most common medications are the following:

  • Methimazole (MMI): This drug is sold in the form of tablets with 5 and 10 milligrams of active ingredient per unit. It inhibits the action of the enzyme thyroperoxidase and prevents the production of thyroxine. During treatment, blood T3 and T4 levels should be monitored and doses adjusted based on them.
  • Propylthiouracil (PTU): It’s recommended when the patient is unable to take MMI – due to hypersensitivity or another condition – as the latter is more effective and reports fewer side effects. It’s always taken with food two or three times a day and the tablets are 50 milligrams.

Beta-blockers

When there’s an overproduction of T3 and T4 in the body, the patient is prone to developing high blood pressure and tachycardia. As indicated by the Radiology Info portal, beta-blockers don’t treat hyperthyroidism, but they do help reduce symptoms.

In other words, beta-blockers help a person feel better while antithyroid drugs restore hormonal balance. Although they’re usually well-tolerated, they can also cause diarrhea, dizziness and headaches.

Radioiodine

Radioactive iodine (I-131), a radiation-emitting isotope of iodine, is used to treat hyperthyroidism and derived goiter. This compound addresses the condition by killing the hyperreactive cells or shrinking the enlarged gland, which stops the excess and overproduction of thyroid hormone.

The professionals who carry out the treatment try to achieve a balance. However, the use of the drug can lead to hypothyroidism. As ironic as it may sound, sometimes the radioactive iodine approach requires hormone replacement therapies.

Hypothyroidism

Hypothyroidism is characterized by an underactive thyroid gland that doesn’t produce enough hormones to meet the body’s needs. Various pathologies can cause hypothyroidism, from Hashimoto’s disease to congenital conditions.

Levothyroxine

Levothyroxine sodium is sold as oral tablets of 50 to 150 micrograms per unit. It’s part of hormone replacement therapy, as it’s a synthetic form of thyroxine.

After starting the treatment with this medicine, blood tests are required to check the level of thyroid hormone in the blood. After successive measurements, levothyroxine treatment usually needs to be taken for life.

T3 and T4 pickups

As indicated by the Hormone.org portal, there are other alternatives to levothyroxine, but they tend to report more disadvantages and aren’t as effective. For example, T3 and T4 pills promote anxiety and their combined action hasn’t been shown to be better than taking T4 in isolation.

Malignant thyroid disease: cancer of the gland

Thyroid cancer occurs when cells in the gland mutate at a genetic level. Due to the changes, these cell lines don’t follow the normal mechanisms of division and senescence, so they multiply uncontrollably. The mutated cells can also invade adjoining tissues or enter the bloodstream, in a process known as metastasis.

Thyroid cancer can be divided into subtypes according to its location (papillary, follicular, anaplastic, medullary, and others). It represents 1% of all types of cancer, but its incidence increases by 4% each year.

Not all thyroid cancers need to be treated, as some remain localized and don’t grow. This is confirmed by the Mayo Clinic.

External radiation therapy

In this approach, a machine directs high-energy beams at specific points on the body. In high doses, the therapy kills cancer cells or slows their growth, but also causes localized damage to harmless tissues. This approach is evaluated when the tumor continues to grow, despite radioactive iodine treatment.

Chemotherapy

Chemotherapy is generally not recommended for thyroid cancer, but it can be used in conjunction with radiation therapy if the tumor is anaplastic. This thyroid neoplasm grows very quickly and can’t be fixed with surgery. The overall prognosis for an anaplastic tumor is very poor. Patients usually don’t live more than 6 months after diagnosis.

Radioactive iod for the thyroid.
Radioactive iodine isn’t always from a single application. Sometimes the process is repeated months or years later in some thyroid pathologies.

Targeted drug therapy

If surgery and radioactive iodine haven’t worked, targeted drug therapy can be used to address this thyroid disease. The American Cancer Society lists the following drugs:

  • Multicinase inhibitors: Lenvatinib (Lenvima ®) and sorafenib (Nexavar ®) are the drugs used in this category. They inhibit the formation of blood vessels that tumors need to grow and attack certain proteins of the cancer cell.
  • RET inhibitors: Selpercatinib (Retevmo ®) and pralsetinib (Gavreto ®) fall into this category. They’re chemical compounds that attack RET proteins, which help the cancer cell to grow. They’re used to treat advanced-stage tumors.
  • NTRK inhibitors: Larotrectinib (Vitrakvi ®) and entrectinib (Rozlytrek ®). They turn off abnormal proteins that help cancer cells grow.

Medications for thyroid disease are many and diverse

There are a number of conditions that can lead to thyroid disease, but many of them use the same drugs. For example, radioactive iodine is used in the treatment of thyroid cancer, hyperthyroidism, and goiter.

Something similar happens with levothyroxine, a synthetic form of thyroxine that has various uses. This drug is useful after the removal of the thyroid in order to treat hypothyroidism and to treat the goiter derived from the latter condition.

Be that as it may, some drugs are useful beyond iodine and levothyroxine, especially when it comes to alleviating the symptoms derived from hyper or hyporesponsiveness of the thyroid. If you have any of these conditions, don’t hesitate to put yourself in the hands of a medical professional.

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