Cytomel®, also known as liothyronine sodium, is a synthetic drug used to treat hypothyroidism, a condition whereby the thyroid gland responsible for regulating the metabolic process in the human body produces low amounts of thyroid hormone. The drug is also used in thyroid diagnostic tests and to treat enlarged thyroid glands that create goiters. Although it is tied to metabolism in the body, the drug is not recommended to treat obesity in patients.
Two hormones are produced by the thyroid gland. One is levothyroxine known as T4 and the other is triiodothyronine known as T3. T4 is usually produced in greater quantities and the body can convert it to T3 easily. Cytomel® is a man-made prescription drug that is identical to the T3 hormone that occurs naturally in the human body. It is taken as a tablet daily. Doctors may monitor a patient’s blood regularly to ensure he or she is receiving the proper dose.
To treat thyroid disorders, most replacement therapies will combine both the T3 and T4 hormones. This is usually done by using hormones made from animal thyroids. Some doctors prefer using manufactured hormones such as Cytomel® because they are less likely to cause allergic reactions since they do not come from animals.
Another benefit of the synthetic version is that thyroid levels can be more precisely controlled. Cytomel® can be combined with T4 medications such as Synthroid® to arrive at the right percentage of both hormones. When T4 is not converted to T3 properly in the body, Cytomel® may be the only solution needed to arrive at the right amount of T3 needed.
Most side effects related to the drug occur when the prescribed dosage is too high, creating an overactive thyroid. This condition is known as hyperthyroidism. Symptoms include headaches, uncontrollable sweating, mood swings and nervous behaviors.
Cytomel® can cause thyroid toxicity, a condition that can cause chest pain, fast heartbeat, hot flashes, anxiety and sweating. Patients who experience allergic reactions in the form of hives, swelling or difficulty breathing should stop using the drug and seek immediate medical attention. Temporary hair loss is a less serious side effect of using the drug.
Women taking birth control pills or on hormone replacement therapy should inform their doctors as these medications can interact with Cytomel®. Blood thinners, insulin and anti-depressants can also interact with the drug. Cytomel® can pass through breast milk, so women who are breastfeeding should consult their doctor before taking the drug.