Thyvex-50/Thyvex-100 Mechanism of Action

Pharmacological Classification: Thyroid Hormone Replacement.
Pharmacology: Pharmacodynamics: THYVEX-50/THYVEX-100 is a tablet containing the hydrated form of Levothyroxine sodium which is used for the treatment of hypothyroidism. The thyroid gland is dependent upon 2 active principles for its main hormone activity these are Levothyroxine (tetraiodothyronine) and Triiodothyronine. These closely related iodine containing amino acids are incorporated into the glycoprotein thyroglobulin. The chief action of these hormones is to increase the rate of cell metabolism. Levothyroxine is deiodinated in peripheral tissues to form Triiodothyronine which is thought to be the active tissue form of thyroid hormone. Triiodothyronine is certainly more rapid acting and has a shorter duration of action than Levothyroxine.
The chief action of Levothyroxine is to increase the rate of cell metabolism.
Pharmacokinetics: Levothyroxine sodium is incompletely and variably absorbed from the gastrointestinal tract. It is almost completely bound to plasma proteins and has a half-life in the circulation of about a week in healthy subjects, but longer during pregnancy in patients with myxoedema. A large portion of the Levothyroxine leaving the circulation is taken up by the liver. Part of a dose of Levothyroxine is metabolized to triiodothyronine. Levothyroxine is excreted in the urine as free drug, deiodinated metabolites and conjugates. Some Levothyroxine is excreted in the faeces. There is limited placental transfer of Levothyroxine.