Liothyronine

Pronounced

"lye-oh-THYE-roe-neen"

Common brand names:

Cytomel

Uses

Liothyronine is used to treat an underactive thyroid (hypothyroidism). It replaces or provides more thyroid hormone, which is normally made by the thyroid gland. Liothyronine is a man-made form of thyroid hormone. Low thyroid hormone levels can occur naturally or when the thyroid gland is injured by radiation/medications or removed by surgery. Having enough thyroid hormone helps you stay healthy. For children, having enough thyroid hormone helps them grow and learn normally.

This medication is also used to treat other types of thyroid problems (such as certain types of goiters, thyroid cancer). It can also be used to test for certain types of thyroid disease.

This medication should not be used to treat infertility unless it is caused by low thyroid hormone levels.

How to Use This Medication

Take this medication by mouth with or without food as directed by your doctor, usually once daily. It is best to take it at the same time each day so your thyroid hormone level is kept at a constant level.

Take this medication regularly to get the most benefit from it. Do not stop taking it without first talking with your doctor. Thyroid replacement treatment is usually taken for life.

The dosage is based on your medical condition, age, lab test results, and response to treatment.

Certain medications can decrease the absorption of liothyronine. Examples include products that contain aluminum or magnesium, antacids, sucralfate, calcium supplements, iron, bile acid-binding resins (such as cholestyramine, colestipol, colesevelam), simethicone, sevelamer, sodium polystyrene sulfonate, among others. If you take any of these medications, take them at least 4 hours before or after liothyronine. If you take lanthanum, take it at least 2 hours before or after liothyronine.

Symptoms of low thyroid hormone levels include tiredness, muscle aches, constipation, dry skin, weight gain, slow heartbeat, or sensitivity to cold. You may see an improvement in these symptoms within a few days. Tell your doctor if you do not get better or if you get worse.

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Information expires December 2025.