Liothyronine is a manufactured form of the thyroid hormone triiodothyronine (T3). It is most commonly used to treat hypothyroidism and myxedema coma. It can be taken by mouth or by injection into a vein.Side effects may occur from excessive doses. This may include weight loss, fever, headache, anxiety, trouble sleeping, arrythmias, and heart failure. Use in pregnancy and breastfeeding is generally safe. Regular blood tests are recommended to verify the appropriateness of the dose being taken.Liothyronine was approved for medical use in 1956. It is available as a generic medication. In 2019, it was the 230th most commonly prescribed medication in the United States, with more than 2 million prescriptions. Medical uses
Liothyronine may be used when there is an impaired conversion of T4 to T3 in peripheral tissues. The dose of liothyronine for hypothyroidism is a lower amount than levothyroxine due it being a higher concentrated synthetic medication. About 25 μg of liothyronine is equivalent to 100 μg of levothyroxine.In thyroid cancer or Graves disease, ablation therapy with radioactive iodine (131I) can be used to remove trace thyroid tissue that may remain after thyroidectomy (surgical excision of the gland). For 131I therapy to be effective, the trace thyroid tissue must be avid to iodine, which is achieved by elevating the persons TSH levels. For patients taking levothyroxine, TSH may be boosted by discontinuing levothyroxine for 3–6 weeks. This long period of hormone withdrawal is required because of levothyroxines relatively long biological half-life, and may result in symptoms of hypothyroidism in the patient.
Pricing
The British Competition and Markets Authority launched an investigation into the alleged "excessive and unfair pricing" of liothyronine tablets in 2017. It alleged that Advanz Pharma overcharged the NHS from before 2007 to July 2017. The price of a pack increased by almost 1,600% from £4.46 before it was debranded in 2007 to £258.19 by July 2017. References
External links
"Liothyronine". Drug Information Portal. U.S. National Library of Medicine.