Thyroid Hormone Replacement Therapy - Tricks of the Trade

Medical Author: Ruchi Mathur, M.D.
Medical Editor: William C. Shiel, Jr., MD, FACP, FACR

Thyroid abnormalities are common and I see many patients with thyroid disease. A large number of these patients suffer from a form of hypothyroidism (low thyroid hormone blood levels) that requires thyroid hormone as replacement therapy. As an endocrinologist (hormone specialist), therefore, I frequently must prescribe thyroid replacement therapy. While the tablets are small and available in many doses to allow for precise dosing, there are a few helpful hints patients should be aware of to assure they are taking their medication properly and achieving the maximum results from their therapy.

Once a stable dose of thyroid replacement has been reached (as indicted by normalization of the thyroid blood tests), this dose may continue for years--if the patient does not take new medications and remains otherwise healthy. A variety of conditions can alter the requirements of thyroid hormone replacement. For example, dosage requirements can decrease with advancing age. A reduction in dosing may also be required in women receiving androgen therapy for breast cancer. Most other conditions require an increase in the dose of thyroid hormone replacement to maintain appropriate blood levels. Many medications can also increase the thyroid hormone replacement needs. Below is a list of some common conditions that can alter thyroid hormone replacement requirements:

Decreased Requirements:

  • Aging
  • Androgen therapy in women (breast cancer therapy)
Increased requirements: Medications: