What happens when you stop taking your thyroid meds?

In this article:

• What are the different types of thyroid medications?
• What happens when you stop taking levothyroxine?
• How can you safely stop taking levothyroxine?
• What happens if you miss a dose of levothyroxine?
• The bottom line

In this article

• What are the different types of thyroid medications?
• What happens when you stop taking levothyroxine?
• How can you safely stop taking levothyroxine?
• What happens if you miss a dose of levothyroxine?
• The bottom line

Hypothyroidism is a common thyroid condition—affecting 5% of the U.S. population—that occurs when your thyroid gland doesn’t produce enough thyroid hormone. If you have felt tired, experienced unexplained weight gain, or are sensitive to cold temperatures, you could be one of millions of Americans with an underactive thyroid. The good news is that this condition is treatable with daily prescription medications like Synthroid (levothyroxine). These drugs replace the body’s missing natural hormones with synthetic hormones to alleviate symptoms. However, there is no cure for hypothyroidism. If you stop taking levothyroxine, your symptoms will return. On top of that, suddenly stopping treatment can lead to potentially serious side effects, such as heart palpitations, hair loss, and dangerously high blood pressure.

What are the different types of thyroid medications?

When patients are diagnosed with hypothyroidism, or an underactive thyroid gland, it’s because their body is unable to produce enough thyroid hormone. There are many causes of hypothyroidism, including autoimmune thyroid diseases, like Hashimoto’s thyroiditis.

On the other hand, hyperthyroidism, or overactive thyroid, happens when too much thyroid hormone is produced. Symptoms of hyperthyroidism include weight loss, loss of appetite, fast heartbeat, nervousness, and irritability.

If a thyroid disorder is suspected, your healthcare provider can order blood tests to measure the level of thyroid hormone (TSH levels) being produced. “Thyroid hormones regulate aspects of metabolism, heart function, and temperature regulation, among other bodily functions,” explains Nirmal Nair, MD, an internist specializing in endocrinology, diabetes, and metabolism with Franciscan Health in Munster, Indiana.

The goal of thyroid hormone medications is to replace the missing thyroid hormones, primarily thyroxine (T4) and triiodothyronine (T3), says Maria Pagan-Mendez, MD, an endocrinologist at Columbia University Irving Medical Center. These hormones are produced in response to thyroid-stimulating hormone (TSH) being released by the pituitary gland. The three main types of thyroid meds are:

1. Levothyroxine: Levothyroxine is the first-line treatment since it is a synthetic form of T4 that the body naturally converts to T3, the active thyroid hormone. “It’s preferred because it is easy to dose accurately, has minimal side effects, and closely mimics natural thyroid function,” Dr. Pagan-Mendez explains.
2. Liothyronine: “Liothyronine is a synthetic form of T3 and may be used alongside levothyroxine in patients who continue to experience symptoms despite adequate T4 replacement,” Dr. Pagan-Mendez says.
3. Desiccated thyroid extract: This extract is derived from pig thyroid glands and contains T4 and T3. “It is less commonly used due to difficulties in regulating the exact dose and increased potential for side effects,” Dr. Pagan-Mendez says.

Levothyroxine is the most commonly used medication for the treatment of hypothyroidism.

What happens when you stop taking levothyroxine?

Like with any medication, levothyroxine has potential side effects such as nausea and fatigue. If you’re experiencing side effects and your hypothyroid symptoms improved, it can be tempting to stop taking this daily Rx.

However, if you stop taking levothyroxine, symptoms of hypothyroidism may return, including:

• Coarse hair
• Dry skin
• Constipation
• Depression
• Dry skin
• Hoarse voice
• Memory problems
• Menstrual cycles that are irregular or heavier than usual
• Muscle weakness, aches, tenderness, and stiffness
• Puffy face
• Sensitivity to cold
• Slowed heart rate
• Thinning hair
• Tiredness
• Weight gain

If you abruptly discontinue the medication without proper medical supervision, you can experience serious complications. For example, “bradycardia, or slow heart rate, and possible heart failure can also occur,” says Cory Rice, DO, founder of Modern Medicine. Underlying cardiovascular disease, especially in the elderly population, can worsen as well. Metabolic issues can lead to changes in a person’s lipid profile.

However, you might not notice any changes immediately. Levothyroxine generally stays in the body for about seven days, Dr. Nair says. Over a few weeks, you may notice the following changes, according to Dr. Nair:

• Week 1: The body starts to feel the absence of thyroid hormone. You may experience fatigue, mild depression, and difficulty concentrating. Some may not notice significant changes yet.
• Week 2: Symptoms intensify. Fatigue, weight gain, and cold intolerance may become more obvious as metabolism begins to slow down as T4 levels decrease.
• Week 3: Cognitive functions may decline further, leading to brain fog, forgetfulness, and mood swings. Physical symptoms like dry skin, hair loss, and muscle weakness may appear.
• Week 4: The metabolic slowdown continues, and you may start gaining more weight if dietary habits remain unchanged. You may experience joint pain and depression as well, he says.
• Beyond week 4: If the hormone remains discontinued, symptoms can continue to worsen.

“Severe fatigue, increased sensitivity to cold, and significant mood disturbances are likely,” Dr. Nair says. “Long-term discontinuation can lead to complications such as myxedema coma, a rare but life-threatening condition characterized by extreme hypothyroidism.”

Additionally, untreated hypothyroidism itself can lead to serious health issues. One study found that patients experienced severe complications that included an accumulation of fluid in the sac that surrounds the heart (pericardial effusion), low hemoglobin levels (anemia), low white blood cell counts (leukopenia), airway obstruction due to swelling of the tongue, and decreased heart rate (bradycardia). These are not the only serious complications associated with untreated hypothyroidism. 

Can you die if you stop taking levothyroxine?

Yes, in rare cases, you can die if you stop taking levothyroxine abruptly and without medical supervision.

“Thyroid hormone should not be stopped altogether when a person is hypothyroid,” says Revital Gorodeski-Baskin, MD, an associate professor at the School of Medicine at Case Western Reserve University. “If this happens, that person will slowly become more and more hypothyroid, and this is very dangerous. In the most extreme case, untreated hypothyroidism can lead to myxedema coma, and this is life-threatening.”

According to the American Thyroid Association, myxedema coma is a medical emergency. Patients are often treated in intensive care units because of the increased risk of death. You may experience very low body temperature, slow heart rate, low blood pressure, a change in mental status, and poor organ function. If patients with this life-threatening condition are not treated promptly, they may not survive.

Individuals with multiple significant health conditions may be at an increased risk of death when discontinuing levothyroxine.“Their medical issues can be exacerbated, and if they are elderly, deconditioned, or otherwise in very poor health, the abrupt cessation of thyroid medication can make their mortality risk much higher,” Dr. Rice says.

How can you safely stop taking levothyroxine?

If you feel you need to stop taking thyroid medications, it’s important to consult with a healthcare professional. “They will determine if it is safe to stop based on your underlying condition,” says Dr. Pagan-Mendez. “In cases where hypothyroidism is no longer present, the medication may be stopped or tapered gradually, with regular monitoring of your thyroid hormone levels to ensure that treatment is no longer needed.”

Some patients can live with hypothyroidism without ever needing thyroid medications. However, this is only the case for people with very mild or borderline hypothyroidism or transient (temporary) hypothyroidism due to inflammation of the thyroid gland or a medication that causes hypothyroidism.

What happens if you miss a dose of levothyroxine?

Accidentally missing a medication dose can happen to anyone. “Missing a single dose generally has minimal impact, but missing multiple doses can lead to a return of hypothyroid symptoms,” says Dr. Pagan-Mendez.

“If a patient misses a thyroid medication dose, the general recommendation is to take the missed dose as soon as they remember, unless it is almost time for their next dose,” explains Dr. Rice.

The bottom line

Taking your thyroid medication is critical for avoiding the short- and long-term complications of hypothyroidism. If you’re experiencing side effects, discuss these issues with your doctor before you stop taking your thyroid drugs.

“Physicians can help adjust the dose, address side effects, and find a dosing schedule that works best for you,” Dr. Pagan-Mendez says. “Open communication ensures that your treatment remains effective and that your symptoms are properly managed.”