Thyroid extract

Thyroid extract is a medication derived from the thyroid glands of animals, typically pigs (porcine thyroid extract) or cows (bovine thyroid extract). It is used to treat thyroid hormone deficiency, including the severe form known as myxedema coma. Thyroid extract contains both of the major thyroid hormones: thyroxine (T4) and triiodothyronine (T3). While synthetic forms of both hormones are available, some practitioners and patients prefer thyroid extract for its "natural" origin and because it provides both T3 and T4, which they believe may better mimic the body's natural thyroid function.

History

The use of thyroid extract dates back to the late 19th century, when it was first used to treat hypothyroidism. Before the availability of pure thyroid hormones, thyroid extract was the only treatment for this condition. Its use has declined since the mid-20th century with the development of synthetic thyroid hormones, which offer more precise dosing and less variability between batches. However, thyroid extract remains in use today, particularly among patients who feel they do not respond well to synthetic hormones.

Indications

Thyroid extract is primarily indicated for the treatment of hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormones. Symptoms of hypothyroidism include fatigue, weight gain, cold intolerance, and depression. Thyroid extract is also used in some cases to treat thyroid cancer, in combination with surgery and other therapies, to suppress the production of thyroid-stimulating hormone (TSH), which can promote cancer growth.

Preparation and Dosage

Thyroid extract is made by drying and powdering the thyroid glands of pigs or cows. The dosage of thyroid extract is measured in grains, with one grain roughly equivalent to 60 mg. The exact dosage varies depending on the individual's needs and is adjusted based on blood tests measuring levels of thyroid hormones and TSH.

Advantages and Disadvantages

Some proponents of thyroid extract argue that it is more effective than synthetic hormones for certain patients, particularly those who have symptoms of hypothyroidism despite normal blood levels of thyroid hormones. They also argue that the presence of T3 in thyroid extract may be beneficial for patients who have difficulty converting T4 to T3.

However, critics of thyroid extract point out that it has several disadvantages, including batch-to-batch variability, the potential for allergic reactions due to its animal origin, and the difficulty of precisely dosing the T3 and T4 hormones. The American Thyroid Association and other medical organizations generally recommend synthetic thyroid hormones over thyroid extract due to these concerns.

Conclusion

Thyroid extract remains a controversial treatment for hypothyroidism and other thyroid-related conditions. While some patients and practitioners prefer it for its "natural" composition and the presence of both T3 and T4, the medical community at large tends to favor synthetic thyroid hormones for their consistency, purity, and ease of dosing. Patients considering thyroid extract should discuss the potential risks and benefits with their healthcare provider.