|Generic Name||Brand Name|
|levothyroxine (T4)||Levothroid, Levoxyl, Synthroid|
|liotrix (T3 and T4)||Euthroid, Thyrolar|
Thyroid hormones are taken by mouth (orally) except in
unusual cases, such as
myxedema coma. That condition requires
intravenous (IV) medicine. Dosages vary with the
person's age and the severity of the disease.
How It Works
hypothyroidism have lower-than-normal or no thyroid
function and do not make enough thyroid hormone for the body to function
properly. Taking thyroid hormone medicine replaces missing hormones.
Why It Is Used
Thyroid hormone medicines are given
when blood tests show that you have hypothyroidism.
medicines also may be prescribed:
How Well It Works
People with hypothyroidism who take
thyroid hormone medicine usually notice:
- Improved energy level.
weight loss (in people with severe hypothyroidism at the time of
- Improved mood and mental function (thinking,
- Improved pumping action of the heart and improved
digestive tract function.
- Reduction in the size of an enlarged
thyroid gland (goiter), if you have one.
- Improved growth, school
performance, and behavior in children. Children whose growth has been delayed
because of hypothyroidism start growing normally again once they get adequate
doses of thyroid hormone.
In most cases, thyroid hormone medicine works quickly to
Myxedema coma can respond well to thyroid
hormone medicine and treatment in an intensive care unit. But a good outcome
depends on how soon treatment starts.
In general, you will not have side
effects if you are taking the correct amount of thyroid hormone
Side effects of too much thyroid medicine
- Heart palpitations.
- Trouble sleeping
- Shaking (tremors).
- Frequent bowel
- Too much weight loss.
- Discomfort in warm
- Bone thinning (osteoporosis)
if the dose is too high for a long time.
Report any side effects to your doctor.
coronary artery disease and you take too much thyroid
medicine, symptoms such as chest pain (angina) or
heart rhythm irregularities (arrhythmia) may get worse. Also, you may have an
increased risk of heart attack.
See Drug Reference for a full list
of side effects. (Drug Reference is not available in all systems.)
What To Think About
Thyroid hormones work best when
they are taken as prescribed. It is best to take your thyroid medicine on an
empty stomach. If you have trouble taking your thyroid medicine as prescribed,
talk to your doctor.
Keep follow-up visits with your doctor to
make sure you are taking the medicine correctly. Your doctor also may need to
adjust your dose. Most people return to their doctor for blood tests to measure
hormone levels 6 to 8 weeks after starting therapy. After thyroid hormone
levels have returned to normal, thyroid function tests are checked once a
Certain medicines can
affect the way thyroid medicines work. People taking the following medicines
need to see their doctor often to make sure they are getting the correct dose
of thyroid hormone medicine. Some of these medicines include:
- Calcium. Take calcium supplements at least 4 hours before or after taking thyroid hormone
- Iron supplements.
- Birth control pills or other hormones.
- Sucralfate and some antacids containing aluminum hydroxide.
- Some seizure medicines.
Hashimoto's thyroiditis, the most common cause of
hypothyroidism, often need treatment for the rest of their lives.
People who have other health conditions in addition to hypothyroidism,
particularly coronary artery disease, may sometimes develop problems if they
are started on a large dose of thyroid hormone. These people are often started
on a lower dose that is carefully increased.
If an infant has
intellectual disability from hypothyroidism, thyroid
hormone medicine will control symptoms of hypothyroidism but will not reverse
the intellectual disabilities.
Too much thyroid hormone medicine can increase bone loss (osteoporosis).
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