What Are The Common Thyroid Medications?

Thyroid problems occur when the thyroid gland in your neck becomes underactive or overactive. This gland produces hormones, including triiodothyronine (T3), tetraiodothyronine (thyroxine or T4), and calcitonin. 

In an underactive thyroid (hypothyroidism), your thyroid produces too few hormones. In an overactive thyroid (hyperthyroidism), your thyroid produces too many hormones. Thyroid medications try to restore normal hormone levels to treat symptoms of thyroid problems. 

What are thyroid medications?

Doctors use several drugs to treat thyroid problems. Medicines that treat overactive thyroid glands decrease the number of hormones they produce. On the other hand, medicines that treat hypothyroidism mimic the hormones they are failing to produce. Furthermore, some drugs treat the symptoms of thyroid problems.  

Drugs for treating hypothyroidism

Levothyroxine

This drug treats hypothyroidism by increasing thyroxine levels. Doctors also recommend it when thyroid hormone levels are normal but thyroid-stimulating hormone (TSH) levels, produced by the pituitary gland, are increased. You will usually take it in pill form in the morning before breakfast. 

Liothyronine

This medication increases triiodothyronine levels and reduces the size of enlarged thyroid glands. 

Liotrix

Liotrix contains mimics of thyroxine (T4) and triiodothyronine (T3).

Thyroid extract

Thyroid extract consists of dehydrated and powered animal thyroid glands. Although medical professionals do not recommend it for treating hypothyroidism, some people consider it a natural option to treat their thyroid problems.

Drugs for treating hyperthyroidism

Propylthiouracil

This drug treats Graves’ disease and hyperthyroidism, which causes the thyroid gland to secrete too much thyroid hormone. This medication stops the thyroid gland from using iodine, which is needed to produce hormones. 

Methimazole

Methimazole (also called carbimazole) stops the thyroid gland from overproducing thyroid hormones. 

What is the most common thyroid medication?

The most common medication for hypothyroidism is levothyroxine. Levothyroxine increases the number of thyroid hormones to bring them up to normal levels. 

Levothyroxine, liothyronine, and liotrix are all effective for treating hypothyroidism.¹ 

These are generally better than thyroid extract, which medical professionals do not usually recommend. The best thyroid medications for an overactive thyroid are propylthiouracil and methimazole. 

How do they affect the body?

All these medications ensure the thyroid gland produces hormones at adequate levels. If you have problems with your thyroid gland, you’ll often notice symptoms such as weight change, rapid heart rates, and changes in mood due to abnormal amounts of thyroid hormone. These thyroid medications will normalize hormone levels and alleviate these symptoms. 

Are thyroid drugs safe?

Thyroid drugs have undergone rigorous testing to ensure they are as safe as possible. Still, many thyroid medications will have side effects, including nausea and headaches. Some drugs should also not be used during pregnancy or breastfeeding as they may affect the baby. However, during pregnancy, levothyroxine is necessary for most women with maternal hypothyroidism to ensure a healthy pregnancy and avoid miscarriage or pre-term birth.²

Thyroid medications that are not suitable for pregnancy include radioactive iodine.³ 

Your doctor will ensure the drug they prescribe is safe for you and help you choose the best one. It is worth remembering that a dysfunctional thyroid gland carries health risks if left untreated. 

What are the side effects of thyroid drugs?

Like most medications, thyroid medications will likely have a few side effects. It can be helpful to talk to your doctor if you are experiencing any side effects. They can change the medication or dosage or prescribe another drug to manage these symptoms. Side effects include: 

• Weight change

• Change in bowel movements

• Mood change

• Feeling feverish

• Headaches

• Palpitations 

Starting thyroid hormone treatment

If your doctor diagnoses you with thyroid problems, they will prescribe thyroid medication according to your condition. If you have an underactive thyroid, treatment will likely involve hormone replacement therapy to increase thyroid hormone levels.

Your doctor may treat an overactive thyroid with medications to decrease the number of hormones produced. Other treatments for an overactive thyroid include radiation therapy and occasionally surgery. 

To start your treatment, your doctor will order blood tests to select an adequate dosage. You may experience a few side effects during the first few weeks while your body adapts to the medication.

How to take your medicine

For most thyroid medication, you take it orally as a pill or liquid. Each medication may be slightly different, but your doctor or pharmacist will show you how to take it. 

You should usually take your medication around the same time each day. Most hypothyroidism medication is best in the morning on an empty stomach, an hour before eating or drinking food.

Drugs that interact with thyroid medicine

When discussing thyroid medications with your doctor, tell them about any other medications or supplements you are taking.

Thyroid medication can interact with certain medications, such as antibiotics. Some food can interfere with thyroid medicine as well. For example, you should avoid ingesting high-calcium foods for a few hours after taking your medication as it decreases how much of the medication your body absorbs. Common interactions include:⁴

• Antibiotics, including rifampin⁵

• Calcium, which decreases the action of some thyroid medication

• Omeprazole which treats stomach ulcers and acid reflux 

The lowdown 

Thyroid medications are effective in treating an underactive or overactive thyroid gland. If your doctor suspects problems with your thyroid gland, they will order a blood test to confirm what medication is best for you. 

Thyroid medications include levothyroxine, liothyronine, and liotrix, all effective for treating an underactive thyroid, and propylthiouracil and methimazole to treat an overactive thyroid.

These medications will likely take some weeks to get the desired results. During this time, pay attention to any side effects, and talk to your doctor if you notice any undesirable effects from this medication.