Medical Health Encyclopedia

A synthetic thyroid hormone called levothyroxine is currently the treatment of choice for hypothyroidism. This drug is a synthetic derivative of T4 (thyroxine), and it normalizes blood levels of TSH, T4, and T3. Nevertheless, the therapeutic principle for hypothyroidism is the same as it was more than 100 years ago: To provide the body with replacement thyroid hormone when the gland is not able to produce enough itself.

Brand Names. A number of levothyroxine brands are available in the US and overseas. Synthroid is the oldest brand and has been used for over 40 years. In the past, manufactures of levothyroxine have not had to meet as strict standards as in the production of other drugs. This resulted in thyroid products with varying quality. The FDA has issued stronger requirements that have largely corrected this problem.

Generics versus Brand-Name Products. Generic brands are available and are subject to the same guidelines as brand-name products. There is still considerable debate over whether generic thyroid preparations are as effective as brand products. For example, brand-name products come in up to 12 different strengths, while generics have less variety from which to choose. Generic brands then may not be appropriate for patients with conditions requiring frequent adjustment of dosages. In addition, the amount of T4 in some generic products is outside the FDA range, which requires additional testing of thyroid hormone levels. Many doctors, then, prefer to use brand-name products, further noting that the cost difference between brand and generic thyroid drugs is not substantial. Regardless of which type is used, once a patient has been stabilized, doctors generally recommend sticking with one type or brand since potency often varies from one drug to the next.

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Natural Thyroid Hormone. Desiccated or dried powdered thyroid hormone (Armour Thyroid, S-P-T, Thyrar, Thyroid Strong) is made from animal glands. It was once the most common form of thyroid therapy but is no longer generally recommended because potency varies. Some people argue that with stricter FDA regulations, this natural form is better controlled and may even reduce the risk of developing autoimmunity factors. Desiccated thyroid also contains both T3 and T4 and is favored as a natural treatment by many alternative practitioners. However, studies need to be conducted to evaluate its benefits.