Hypothyroidism and Levothyroxine (LT4)

Levothyroxine is a commonly prescribed treatment for hypothyroidism. It is a thyroid replacement therapy to address low T3 hormone levels.

Brand names of Levothyroxine include:

• Synthroid
• Levothroid
• Levoxyl
• Unithroid

Levothyroxine (LT4) is a thyroid hormone replacement therapy which addresses low T4 thyroid hormone levels in the body. This type of thyroid hormone replacement therapy is more common than Liothyronine (T3), a thearpay for replacement of low T3 thyroid levels.

Read more details about Levothyroxine (LT4).

Levothyroxine is taken once a day. The dose of levothyroxine is based on your thyroid function tests, age, weight, the presence of any heart conditions, and the presence of remaining thyroid gland. Getting to the right dose can take time, as it is very individual and the range of the correct dosage is narrow. The dosage is gradually increased every 6-8 weeks until the blood levels of TSH is in the normal range.

If you are elderly or have a heart condition, your doctor will start with a very lower dose to give your body a chance to get used to the higher thyroid hormone level. After you have reached normal levels of TSH, your doctor may want to see you at least twice a year to make sure your levels continue to be in the normal range. Sometimes, thyroid blood levels can get higher or lower over time, making it necessary to increase or decrease the dosage of medicine.

You may begin to feel better within one to two weeks after starting medication, but often it can take longer. In fact, it may take three to six months after your blood levels are normal before you really feel well. Once this happens, you must continue to levothyroxine, as hypothyroidism is not curable. You will likely need thyroid hormones for the rest of your life. Remember to take your thyroid medication on an empty stomach since calcium, iron, soy, and multivitamins in the stomach will interfere with its absorption. Do not take it along with any diary, iron, or soy products as they can also interfere with absorption.

Once you start on a certain brand of levothyroxine, you should stay on that brand; the same dose of another brand may be absorbed differently in your body. If you change your dose or brand, you will be asked to have your blood levels of TSH checked about six weeks later.