The human thyroid gland produces two major hormones: triiodothyronine and thyroxine. In patients with hypothyroidism, where the function of the thyroid is low, synthetic versions may be needed to replace missing hormones in the body. Replacement of triiodothyronine is done using liothyronine sodium, which is marketed under the brand name Tertroxin.
Thyroid hormones are critical for the body to function correctly, affecting the body's metabolism, temperature, and brain function; therefore, those with hormone deficiencies generally need to be on these drugs their entire lives. Dosage of the drug varies from patient to patient, as many factors can play a role in how much is needed. Some of these variables include the patient's age, weight, and how much hormone their body already produces naturally. A doctor will start with an initial dose and then adjust it depending on how the patient responds. Tertroxin may be prescribed in conjunction with levothyroxine, the synthetic form of thyroxine.
Side effects from Tertroxin can be severe and unpleasant, though they happen most frequently when the dosage of the drug is too high and its presence in the body mimics hyperthyroidism. Some patients may experience an elevated heart rate and chest pains. They may feel nervous and have tremors or excessive sweating. Nausea, vomiting, and diarrhea can occur. Menstruation may be affected in some women, with periods becoming irregular.
Another effect that many people experience on Tertroxin is weight loss. This is due to the drug's tendency to increase one's metabolism. In some cases, the drug is prescribed to treat obesity for this reason. This effect also makes it attractive to bodybuilders interested in eliminating any extra body fat to emphasize their muscles; it is therefore sometimes used in conjunction with steroids to produce a more sculpted body.
People taking this drug need to use caution when combining it with certain other drugs, as the interaction can impact the effectiveness of one or the other. Some blood thinners may become more active when combined with it, which can put the patient at risk of excessive bleeding. The bronchodilator Theophylline, used to treat asthma, may not work as well when combined with the thyroid medication, and doses may need to be monitored and adjusted. Digoxin, which helps strengthen heart rate, can also become less effective as thyroid hormone levels increase in the body. Certain cholesterol-lowering medications may make Tertroxin less effective when they are taken together.