How Hypothyroidism Is Treated

Autoimmune Hashimoto's disease is the most common cause of an underactive thyroid gland, and there are several causes ​for it. Regardless, the treatment for an underactive thyroid gland, surgically removed gland, or congenitally damaged or missing gland is thyroid hormone replacement with a prescription thyroid drug. 

Once a person begins thyroid hormone replacement medication, the goals of treatment are quite simple. They include:

  • Normalizing thyroid hormone levels, specifically, thyroxine (T4) and thyroid stimulating hormone (TSH) levels
  • Eliminating symptoms of hypothyroidism, like constipation, fatigue, and cold intolerance
  • Halting and reversing any effects that hypothyroidism may be having on various organ systems (for example, elevated cholesterol levels)
  • Reducing the size of a goiter, if present, as is sometimes the case with Hashimoto’s disease

Levothyroxine (T4)

Hypothyroidism is treated by prescribing an oral thyroid hormone preparation (usually levothyroxine, a T4 preparation). The dosage should be sufficient enough to restore normal thyroid hormone levels without producing toxicity from too much thyroid hormone.

Formulations

There are different formulations of T4 made by different manufacturers. While all FDA-approved formulations are judged to be suitable, most experts recommend sticking to the same formulation you start on, since the dosage equivalents may vary somewhat among different preparations.

In the United States, levothyroxine is available as generic levothyroxine, as well as Synthroid, Levothroid, and Levoxyl brand name tablets. Tirosint is a liquid gel cap form of levothyroxine that has been on the market since 2011.

Dosing

In young, healthy people, doctors will generally begin with what is estimated to be a “full replacement dose” of T4 (that is, a dose that is supposed to completely restore thyroid function to normal). The full replacement dose is estimated according to body weight and, for most people, is between 50 and 200 micrograms (mcg) per day.

In older people or those with coronary artery disease, the initiation of thyroid replacement therapy is usually done more gradually, beginning with 25 to 50 mcg daily and increasing over time.

T4 for Younger People

  • Between 50 and 200 micrograms (mcg) per day

  • Begins with a full replacement dose

T4 for Older People

  • Between 25 and 50 micrograms (mcg) per day

  • Dose begins low and gradually gets increased

Administration

People should take T4 on an empty stomach to prevent the absorption of the medication from being erratic. Moreover, doctors usually recommend taking the medication first thing in the morning, then waiting at least an hour to eat breakfast or drink coffee. Taking the medication at bedtime, several hours after the last meal, also appears to work and may be a more convenient approach for some people.

Monitoring

TSH levels are monitored to help optimize the dose of T4. TSH is produced by the pituitary gland in response to thyroid hormone levels. So when thyroid hormone levels are low (as in hypothyroidism), TSH levels respond by increasing, in an attempt to “whip” more thyroid hormone out of the thyroid gland.

When hypothyroidism is adequately treated, TSH levels typically drop back down into the normal range. So, a mainstay in determining the best dose of T4 is measuring TSH levels.

While symptoms of hypothyroidism usually begin to resolve within two weeks of initiating treatment, it takes about six weeks for TSH levels to stabilize. That is why TSH levels are generally measured six weeks after treatment has begun.

If TSH levels remain above the target range, the dose of T4 is increased by about 12 to 25 mcg per day, and TSH levels are repeated after six more weeks. This process is continued until the TSH level reaches the desired range and symptoms are resolved.

Once the optimal dose of T4 is settled upon, TSH levels are measured every year or so thereafter, to make sure the treatment remains optimized. 

Liothyronine (T3)

While the standard approach to treating hypothyroidism (T4 replacement) works for most people, some people continue to experience symptoms. 

In fact, according to a 2016 study published in the Journal of Clinical Endocrinology and Metabolism, about 15 percent of people in the United States with hypothyroidism continue to feel unwell despite being treated for the disease.

Some doctors may then consider liothyronine (T3) as an add-on treatment for select individuals, though this is a matter of debate.

The Controversy

T4 is the major circulating thyroid hormone, but it is not the active hormone. T4 is converted to T3 in the tissues as needed. And T3 is the thyroid hormone that does all the work. T4 is merely a prohormone—a repository of potential T3 and a way of making sure that enough T3 can be created on a minute-to-minute basis as it is needed.

When doctors give T4 and not T3, they are “trusting” the tissues of the person with hypothyroidism to convert just the right amount of T4 to T3 at just the right place and at just the right time. 

However, there is emerging evidence suggesting that, at least in some people with hypothyroidism, that efficient conversion of T4 to T3 is lacking. In other words, despite the fact that their T4 levels may be normal, their T3 levels may be low, especially in the tissues, where T3 actually does its work.

Why T4 to T3 conversion may be abnormal in some people is, at this point, largely speculation—although at least one group of patients has been identified with a genetic variant (in the diodinase 2 gene) that reduces the conversion of T4 to T3.

In any case, it appears that doctors should be treating at least some people (albeit, a small group, most likely) who have hypothyroidism with both T4 and T3.

Formulations

Liothyronine is a synthetic form of T3, and it is available in a manufactured form as the brand Cytomel, and also as generic liothyronine. T3 can also be compounded.

Dosing

Giving appropriate doses of T3 is trickier than appropriately dosing T4. T4 is inactive, so if you give too much there is no immediate, direct tissue effect. T3 is a different story, though, as it is the active thyroid hormone. So if you give too much T3, you can produce hyperthyroid effects directly—a risk, for instance, to people with cardiac disease. 

When adding T3 to T4 during thyroid replacement therapy, most experts recommend administering a ratio of T4:T3 of between 13:1 to 16:1, which is the ratio that exists in people without thyroid disease. 

Monitoring

In people taking combined T4/T3 therapy, doctors usually check a TSH level six weeks after beginning treatment. T3 levels are not generally checked because currently-available T3 formulations lead to wide fluctuations in T3 blood levels throughout the day. 

Desiccated Thyroid Extract

Desiccated thyroid extract contains both thyroxine (T4) and triiododothyronine (T3), and is derived from the thyroid glands of pigs.

Formulations

Several brands of desiccated thyroid are available by prescription in the United States and in some other countries, including Naturethroid, WP Thyroid, Armour Thyroid, a generic NP Thyroid (made by manufacturer Acella), and a Canadian natural thyroid from manufacturer Erfa.

Important Note

While desiccated thyroid extract is available as a prescription, it's rarely recommended by doctors anymore, as there is no scientific evidence it has any benefits over synthetic T4.

Moreover, the ratio of T4 and T3 in desiccated thyroid extract (about 4 to 1) is not the same as the human ratio (about fourteen to 1). In other words, even though desiccated thyroid extract is often spouted as "natural," it's ratio of T4-to-T3 hormone does not mimic that of human physiology.

For Infants

In an infant diagnosed with congenital hypothyroidism, the objective is to restore thyroid levels to normal as quickly and safely as possible. The quicker the thyroid levels are normalized, the more normal the cognitive and motor skills development of the infant.

Levothyroxine is the treatment of choice for congenital hypothyroidism. 

Administration

Often, a liquid form of levothyroxine is given to infants.

It's important to not mix the levothyroxine with soy infant formula or any calcium or iron-fortified preparations. Soy, calcium, and iron can all reduce the infant's ability to absorb the medication properly.

If levothyroxine tablets are given to an infant, parents should crush the levothyroxine tablet and mix it with breast milk, formula, or water that's fed to the baby.

Monitoring

Children being treated for congenital hypothyroidism are evaluated on a regular schedule, often every several months for at least the first three years of life.

According to the European Society for Paediatric Endocrinology, in congenital hypothyroidism, serum T4 or free T4 and TSH blood tests should be performed at the following times:

  • Every one to three months during the first 12 months of life
  • Every one to four months between 1 and 3 years of age
  • Every six to 12 months thereafter until growth is complete
  • Every two weeks after the initiation of T4 treatment, and every two weeks until TSH level is normalized
  • Four to six weeks after any change in dose
  • At more frequent intervals when compliance is questioned or abnormal results are obtained

Permanent or lifelong congenital hypothyroidism can be established by imaging and ultrasound studies showing that the thyroid is missing or ectopic, or a defect in the ability to synthesize and/or secrete thyroid hormone is confirmed.

If permanent hypothyroidism has not been established, levothyroxine treatment may be discontinued for a month at age 3, and the child retested. If levels remain normal, transient hypothyroidism is presumed. If levels become abnormal, permanent hypothyroidism is assumed.

Children with transient congenital hypothyroidism who are taken off medication should, however, still have periodic thyroid evaluation and retesting, as these children face an increased risk of developing a thyroid problem throughout their lives.

In Pregnancy

In order to protect your pregnancy and the health of your baby, it is essential that a woman has sufficient thyroid hormone throughout her pregnancy.

Before Pregnancy

According to guidelines from American Thyroid Association, the dosage of thyroid hormone (levothyroxine) replacement medication for a woman with pre-existing hypothyroidism should be adjusted so that her TSH level is below 2.5 mIU/L prior to conception.

During Pregnancy

The traditional reference range used by the doctor to diagnose and manage hypothyroidism is significantly narrower in pregnancy. 

The TSH level should be maintained at the following trimester-specific levels:

  • First trimester: Between 0.1 and 2.5 mIU/L
  • Second trimester: Between 0.2 to 3.0 mIU/L
  • Third trimester: Between 0.3 to 3.0 mIU/L

Complementary Alternative Medicine (CAM)

In addition to the traditional treatment of your hypothyroidism with thyroid hormone replacement, implementing lifestyle habits, mind-body practices, and dietary changes in your health care can offer many benefits.

For example, some experts suggest that certain yoga poses (specifically, shoulder stands and inverted poses where the feet are elevated) may be beneficial to blood flow to the thyroid gland, or to the reduction of general stress that contributes to worsening symptoms of hypothyroidism.

Moreover, some people find that guided meditation is helpful for the thyroid, as are other stress-reducing strategies like prayer, gentle yoga, tai chi, and needlework. 

It's important to be open and honest with your doctor from the start about your use of complementary therapies, so you can ensure that nothing you're doing (or want to try) will interfere with your thyroid care.

Self-Treatment

It's important to note that self-treating your thyroid problem with supplements and/or making a few dietary changes is not a good idea. Treating an underactive thyroid is a complex process that requires careful symptom and dose monitoring by a physician.

Keep in mind, as well, that supplements are not regulated by the government, meaning there is no scientific consensus that they are safe and effective. In other words, just because a supplement is "natural" or available without a prescription does not necessarily mean it's actually harmless.

Lastly, while some holistic or CAM practitioners may be able to recommend approaches to support your thyroid, immune and hormonal systems, it's important to be cautious of any product that's marketed as a "cure" for your disease, or one that's said to have no side effects.

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