What is Liothyronine?

In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects .

Liothyronine is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. It is also used to help decrease the size of enlarged thyroid glands (known as goiter) .

Liothyronine is also used in some medical tests to help diagnose problems with the thyroid gland .

This medicine is available only with your doctor's prescription .

This medicine usually needs to be taken for the rest of your life. Do not stop taking this medicine or change your doses without first checking with your doctor. It may take several weeks before you start to notice an improvement in your symptoms .

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For oral dosage form (tablet):
  • For the treatment of mild hypothyroidism:
    • Adults—At first, 25 micrograms (mcg) once a day. Doses may be increased by up to 25 mcg every 1 or 2 weeks. However, the dose usually is not more than 75 mcg once a day.
    • Children—Use and dose must be determined by your doctor .
  • For the treatment of myxedema:
    • Adults—At first, 5 mcg once a day. Doses may be increased by 5 to 10 mcg daily every 1 or 2 weeks. When the daily dose of 25 mcg is reached, dosage may be increased by 5 to 25 mcg every 1 or 2 weeks as needed. However, the dose usually is not more than 100 mcg once a day.
    • Children—Use and dose must be determined by your doctor .
  • For the treatment of congenital hypothyroidism:
    • Adults and children over 3 years of age—Use and dose must be determined by your doctor.
    • Children—At first, 5 mcg once a day. Dosage may be increased by 5 mcg every 3 or 4 days as needed.
    • Children 0 to 1 year of age—20 mcg once a day for maintenance.
    • Children 1 to 3 years of age—50 mcg once a day .
  • For the treatment of simple (non-toxic) goiter:
    • Adults—At first, 5 mcg once a day. Doses may be increased by 5 to 10 mcg daily every 1 or 2 weeks. When the daily dose of 25 mcg is reached, dosage may be increased by 12.5 to 25 mcg every 1 or 2 weeks as needed. However, the dose usually is not more than 75 mcg once a day.
    • Children—Use and dose must be determined by your doctor .

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Appropriate studies performed to date have not demonstrated pediatrics-specific problems that would limit the usefulness of liothyronine in children .

Appropriate studies performed to date have not demonstrated geriatrics-specific problems that would limit the usefulness of liothyronine in the elderly. However, elderly patients are more likely to have age-related kidney or heart problems, which may require adjustment of dosage in patients receiving liothyronine .

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Midodrine

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Kelp

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Adrenal insufficiency (untreated) or
• Thyrotoxicosis (untreated; overactive thyroid)—This medicine should NOT be used in patients with any of these conditions .

• Clotting disorders or
• Diabetes or
• Heart disease (history of) or
• Hypogonadism (underactive ovary or testis) or
• Kidney problems (e.g., nephrosis) or
• Myxedema (skin or tissue disorder caused by hypothyroidism) or
• Other adrenal gland problems or
• Underactive pituitary gland—Use with caution. Dosage adjustment may be needed .

It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood and urine tests will be needed to check for unwanted effects .

Liothyronine should not be used for the treatment of obesity or for the purpose of losing weight. This medicine is ineffective for weight reduction and when taken in larger amount, it may cause more serious medical conditions .

Hypothyroidism can sometimes cause infertility in men and women. Liothyronine should not be used for the treatment of infertility unless it is caused by hypothyroidism .

Call your doctor right away if you start to have chest pain, fast or irregular heartbeat, excessive sweating, heat intolerance, nervousness, or any other unusual medical condition .

For patients with diabetes, it is very important that you keep track of your blood or urine sugar levels as instructed by your doctor. Check with your doctor immediately if you notice any changes in your sugar levels .

A temporary loss of hair may occur during the first few months of liothyronine therapy. Ask your doctor about this if you have any concerns .