What Is Thyroxine Sodium?

Thyroxine sodium is a generic name for a synthetic thyroid hormone drug that addresses low levels of naturally occurring thyroxine or T₄. This is not the best-known generic name of the medicine, and many people are more familiar with levothyroxine or the brand name Synthroid®. In any form, patients must carefully follow special dosing instructions to avoid inactivating the drug. Additionally, this medication has noted health condition and medication interactions, plus mild to severe side effects.

There are generally three conditions for which people might be prescribed thyroxine sodium. Hypothyroidism or very low levels of T₄ could indicate its use. People with the autoimmune disorder Hashimoto’s thyroiditis also take this drug. A person born without a functioning thyroid or who has had this gland removed via surgery or radioactive iodine needs replacement of T₄, too.

This medication is prescribed in tiny amounts, usually measured in micrograms. It is often taken in the morning, though some people split their doses. Thyroxine sodium can only be swallowed with plain water, and it needs to be taken on an empty stomach or at least two hours after eating. Patients should not eat for a half hour to an hour after they take a dose of this drug. It’s important to be aware that food or juice can seriously affect the integrity of the medication and result in a persistence of hypothyroidism.

Some warnings accompany the use of this medication. It can cause weight loss, which has tempted some physicians to prescribe it to overweight patients who do not have low T₄ levels. This may trigger hyperthyroidism and is very dangerous. Concerns also exist about using lithium with thyroxine sodium, but this is frequently prescribed. Patients should simply have their thyroid levels monitored regularly because lithium may occasionally increase or decrease thyroid hormone production.

Additional medications may interact with thyroxine sodium, including many blood thinners, antidepressants, hormones, and steroids. Oral drugs for diabetes might require adjustment or monitoring if they are used with a synthetic thyroid hormone. To avoid other dangerous interactions, people are advised to tell their doctors about all drugs and supplements they use.

Most people don’t notice many side effects of thyroxine sodium, provided they are taking it in appropriate amounts. They may have more energy and sometimes hair loss increases slightly. On the other hand, if too much T₄ is present, symptoms could include severe weight loss, serious hair loss, and heart palpitations. Other dangerous signs that require medical attention are headaches, changes in menstrual periods, sleeplessness, and extreme irritability. To avoid these symptoms, doctors should regularly check both thyroid stimulating hormone (TSH) and T₄ to be certain these fall within the normal range.

Over time, synthetic T₄ may have some cumulative undesirable effects. It tends to decrease bone density, and women, especially, may become more prone to osteoporosis and fractures. When used in children this drug has also been associated with stunting of growth. These complications are not thought to be as dangerous as sustained hypothyroidism. Thus, they usually don’t affect the frequency with which this medication is prescribed.