Levoxyl (levothyroxine sodium) is a medicine that is a manufactured version of levothyroxine, a thyroid hormone. It is available only with a prescription and is used to treat the following conditions:

Goiters (including thyroid nodules)
Underactive thyroid (known medically as hypothyroidism)
Certain types of thyroid cancer (when used with surgery or other treatments).

Levoxyl Uses for Hypothyroidism
An underactive thyroid (hypothyroidism) is a common disorder of the thyroid gland. It can occur as the result of two very different problems. It can occur due to problems that cause the thyroid to become underactive (such as an inflammation of the thyroid), or it can be caused by treatments for other thyroid problems, such as an overactive thyroid (hyperthyroidism). Part of the thyroid is often intentionally destroyed (using surgery or other treatments) in an effort to treat cancer, nodules, or hyperthyroidism. However, it is common to destroy too much of the thyroid, leaving people with an underactive thyroid.

Either way, the end result is the same -- the thyroid does not produce enough thyroid hormones, which results in the following hypothyroidism symptoms:

Coarse, dry hair
Skin that is dry, rough, and pale
Fatigue and weakness
Feeling cold all the time
Weight gain
Constipation
A decreased sex drive
Muscle cramps
Hair loss
Changes in the menstrual cycle
Depression
Irritability
Memory loss.

As you can see, many of these symptoms can be subtle, and many people blame their symptoms on aging or stress, without realizing they have a thyroid problem. Levoxyl works to boost the body's thyroid hormone levels, which can work wonders for the symptoms of hypothyroidism. However, do not expect results overnight; it often takes several weeks to notice any improvement. Levoxyl should never be used to increase energy or cause weight loss in people without a thyroid problem.

It is important to understand that with Levoxyl, more is not necessarily better. Taking too much will cause symptoms of hyperthyroidism, some of which can be quite dangerous. This is why your healthcare provider will carefully monitor you (using blood tests) to make sure you are not taking too much or too little Levoxyl.

Levoxyl is used off-label in conjunction with antidepressants to treat depression (particularly depression that has been resistant to other treatments).

It is important to note that Levoxyl should not be used as a weight loss medication in people without thyroid problems. Normal Levoxyl doses are not likely to cause significant weight loss; weight loss is only seen at doses high enough to cause serious Levoxyl side effects. Also, Levoxyl should not be used to treat infertility, unless it is related to a thyroid problem.

Some of the warnings and precautions to be aware of prior to taking Levoxyl include the following:

Levoxyl is a "narrow therapeutic index" medication. This means that for any given person, the range of Levoxyl doses that are both safe and effective is small. Even tiny changes in doses can cause significant problems (either making Levoxyl ineffective or causing serious side effects). Your healthcare provider should carefully and slowly adjust your dose, and should monitor your progress often using blood tests. Even if you have been stable on Levoxyl for years, your healthcare provider should still do these blood tests regularly.

The medication can make heart problems worse. If you have heart problems, your healthcare provider should start you at a low Levoxyl dosage and slowly increase it. If you notice that Levoxyl makes your heart symptoms worse, let your healthcare provider know right away.

People who do not have thyroid problems should never use Levoxyl to lose weight. A Levoxyl dosage high enough to cause weight loss in these people is often high enough to cause serious or even life-threatening problems.

Levoxyl should not be used to treat goiters or thyroid nodules in people who have a low level of thyroid-stimulating hormone (TSH), as it could cause dangerous side effects. A low TSH level signals that thyroid hormone levels are already high, and adding Levoxyl could cause them to increase to a dangerous level. Even if the TSH level is normal, frequent monitoring is required to make sure problems do not develop.

Levoxyl may increase the risk of osteoporosis, particularly if your Levoxyl dose is too high. This is one of the reasons why it is a good idea for your healthcare provider to prescribe a dose of Levoxyl that is just enough to return your thyroid hormone levels to normal.

Sometimes, thyroid problems occur in conjunction with other health problems (such as anemia or diabetes). It is a good idea for your healthcare provider to give you a thorough physical when you are diagnosed with a thyroid problem.

It often takes Levoxyl several weeks to start working. Try not to get frustrated if you are not feeling better more quickly.

If you have diabetes, it is a good idea to check your blood sugar more often when starting or stopping Levoxyl (or when changing your dose), as the medication can affect your blood sugar levels.

Levoxyl can potentially interact with many other medications.
Levoxyl is considered a pregnancy Category A medication. This means that it is probably safe for use during pregnancy.

Levoxyl does pass through breast milk in humans, although it is not likely to cause problems. If you are breastfeeding or plan to start breastfeeding, discuss this with your healthcare provider prior to taking the drug.