Thyroid drugs (thyroid hormones) are used to supplement low thyroid levels in people with hypothyroidism.
Hypothyroidism is a condition in which the thyroid gland does not produce enough thyroid hormones to meet the needs of the body. Doctors may use the term “an underactive thyroid gland” to describe hypothyroidism.
Our thyroid gland is a butterfly-shaped gland that is located just below the Adam’s apple, along the front of the windpipe. Even though thyroid hormones are made in the thyroid gland, the production of these hormones is regulated by another hormone, called thyroid stimulating hormone (TSH), which is made by the pituitary gland (a pea-shaped organ found at the base of the brain). If thyroid hormone levels are low, then our metabolism and many other body functions slow down.
Another condition, called hyperthyroidism, is when the thyroid produces too much thyroid hormone. Although hyperthyroidism seems to be the opposite of hypothyroidism, the link between them is complex, and one can lead to the other in certain circumstances.
What are thyroid drugs used for?
Thyroid drugs are used to treat hypothyroidism, also referred to as an underactive thyroid.
Even though the thyroid produces two hormones, T3 and T4, T4 is most commonly prescribed to treat hypothyroidism.
The only way to test for hypothyroidism is with a blood test, as symptoms vary significantly between people and are similar to several other conditions.
Symptoms of hypothyroidism include:
Cold intolerance
Constipation
Decreased sweating
Dry skin
Frequent urinary and respiratory tract infections
Heavy periods
Joint and muscle pain, cramps, or weakness; slowed movements
Loss of sex drive
Puffy face, feet, and hands
Sleeplessness (insomnia)
Slowed heart rate
Thin brittle hair or fingernails
Tiredness and fatigue
Weight gain.
If hypothyroidism develops in children or teenagers it may affect their growth; interfere with learning and brain development; and delay tooth development and puberty.
What are the differences between thyroid drugs?
Thyroid hormone preparations can be divided into two categories:
Natural preparations derived from animal thyroid
Synthetic preparations manufactured in a laboratory.
Natural preparations include desiccated thyroid and thyroglobulin.
The most common medication used for supplementation is synthetic thyroxine, also called levothyroxine. This is identical to the T4 hormone. T4 is converted into T3 in the body.
Liothyronine (T3, also called triiodothyronine) is another thyroid hormone that may be prescribed to people who are unable to properly convert T4 into T3.
Liotrix was a combination of levothyroxine (T4) and liothyronine (T3) in a 4:1 ratio. It has been discontinued.
Ingredients
Brand name examples
levothyroxine
Levoxyl, Synthroid, Unithroid
liothyronine
Cytomel, Triostat
thyroid desiccated
Armour-thyroid
It is important that levothyroxine is taken on an empty stomach at least 30 to 60 minutes before breakfast to ensure that it is absorbed properly. It should be taken with a big glass of water, and spaced apart by at least four hours from antacids or supplements such as calcium or iron.
Are thyroid drugs safe?
Thyroid medicines are safe when taken at the recommended dose and prescribed by a doctor. You must ONLY take what your doctor recommends. The correct dosage for you is based on your age, health, current natural thyroid hormone levels, and weight.
When you first start treatment for hypothyroidism, your doctor will regularly monitor the levels of different thyroid hormones in your blood to determine if your dosage of thyroid medication needs adjusting. Once the correct dosage has been established for you, the frequency of these blood tests will decrease. Thyroid drugs are generally taken for life.
It will take a few months for your thyroid levels to get back to normal but as long as you are taking your thyroid drugs as prescribed, then you should not have many side effects. Side effects generally happen because you are taking too much thyroid hormone.
Thyroid hormones should NEVER be taken by people without thyroid problems to treat obesity or for weight loss. Some fatalities have occurred when they have been used if these drugs are taken in large dosages for this indication.
Be aware that some supplements marketed as supporting thyroid health may actually contain undisclosed thyroid hormones. Taking these in addition to your thyroid medications may cause toxicity. Thyroid drugs have also been serendipitously added to supplements labeled as only containing animal tissue or herbs such as ashwagandha, guggul, and Coleus forskohlii. Even seaweed-containing products, such as kelp, contain high levels of iodine which can interfere with thyroid function. If you are taking thyroid drugs, always talk with your doctor before taking any supplement.
Also, talk to your doctor about your diet. Some people with hypothyroidism are particularly sensitive to the effects of iodine, and it may trigger or worsen hypothyroidism. In addition, high fiber diets and certain types of foods such as soy or cruciferous vegetables may affect how your body responds to thyroid drugs.
What are the side effects of thyroid drugs?
Thyroid drugs don’t tend to cause side effects if taken at the right dose. Side effects are an indication that you may be taking too much thyroid hormone and may include:
A fast heartbeat
Difficulty sleeping
Dull, lifeless, or brittle hair
Heat sensitivity
Hunger
Nervousness or anxiety
Shakiness
Sweating
Tiredness
Weight loss.
If you develop any of these side effects talk to your doctor about a blood test to check your thyroid hormone levels.
Data
Source:drugs.com
Methimazole
Methimazole is a medication used to treat hyperthyroidism, a condition where the thyroid gland produces an excessive amount of thyroid hormone. It works by inhibiting the production of thyroid hormones in the thyroid gland. Methimazole helps to control symptoms such as rapid heartbeat, weight loss, and tremors associated with hyperthyroidism. It is usually taken orally and requires regular monitoring of thyroid hormone levels to ensure proper dosage.
Propylthiouracil is a medication used to treat hyperthyroidism, a condition where the thyroid gland produces an excessive amount of thyroid hormone. It works by inhibiting the production of thyroid hormone in the thyroid gland. This helps to normalize the levels of thyroid hormone in the body and alleviate symptoms such as rapid heartbeat, weight loss, and tremors. Propylthiouracil is typically taken orally and requires regular monitoring of thyroid hormone levels to ensure proper dosage.