The thyroid gland, which is found in the neck, produces a hormone that keep cells healthy. When the thyroid isn't able to produce enough of that hormone, a condition called hypothyroidism, doctors prescribe hormone replacement therapy. Levothyroxine and Cytomel are two types of thyroid hormone replacement medications that can benefit people with thyroid conditions.
Benefits of Levothyroxine
Levothyroxine is the generic name for thyroxine, or T4. It is the most commonly prescribed synthetic replacement for the lost thyroid hormones naturally produced in the body, because it provides the most consistent level of the hormone in the body, according to the "Journal of the American Medical Association." It is often sold as Synthroid or Levothroid. MayoClinic.com says it may take a while before the effects of low thyroid hormone levels are seen. These effects include heart disease, infertility, obesity and joint pain. Levothyroxine, taken at the prescribed dosage, reverses these effects. This drug is also used to reduce the size of a goiter, a thyroid gland enlargement that may result from cancer or radiation treatments.
Benefits of Cytomel
Cytomel is the brand name for liothyronine, or T3, another thyroid replacement hormone. Like levothyroxine, Cytomel can reverse the symptoms of hypothyroidism and treat goiter, but is not as commonly prescribed, because it is more difficult to maintain the correct dosage level. Liothyronine is also used in tests for hypothyroidism. According to Drugs.com, neither liotyronine nor levothyroxine should be used to treat obesity in those with normally functioning thyroid glands, as this will lead to complications.
Benefits of Combined Therapy
Liothyronine and levothyroxine have sometimes been prescribed in combination. On his website, Dr. Gary Pepper cites a 1999 article in the "New England Journal of Medicine," along with his own clinical experience, in arguing that combining T3 and T4 thyroid hormones improves mood and some aspects of cognitive functioning versus T4 replacement alone. According to a 2003 article in the "Journal of the American Medical Association," however, the combination shows "no beneficial changes in body weight, serum lipid levels, hypothyroid symptoms as measured by a HRQL questionnaire, and standard measures of cognitive performance."