Although both T4 (thyroxine, an inactive form that is converted to T3 in other areas of the body) and T3 (triiodothyronine, the active form) are secreted by the normal thyroid gland, many hypothyroid patients are treated only with levothyroxine (synthetic T4). Some hypothyroid patients remain symptomatic, and T3 may also be required for optimal thyroid replacement therapy. However, the only commercially available form of T3 is liothyronine sodium in an immediate release formulation which is rapidly absorbed, and may result in higher than normal T3 concentrations throughout the body causing serious side effects, including heart palpitations.
Research indicates there is a need for sustained-release T3 preparations in order to avoid adverse effects. A randomized, double-blind, crossover study found inclusion of T3 in thyroid hormone replacement improved cognitive performance, mood, physical status, and neuropsychological function in hypothyroid patients. Two-thirds of patients preferred T4 plus T3, and tended to be less depressed than after treatment with T4 alone. Patients and their physicians may wish to consider the use of sustained-release T3 in the treatment of hypothyroidism, particularly when the response to levothyroxine (T4) has not been complete. (J Endocrinol Invest 2002 Feb;25(2):106-9; N Engl J Med 1999 Feb 11;340(6):424-9)
Many patients have tried commercially available thyroid hormones, such as levothyroxine and liothyronine, and have found that a combination of T4 and T3 is the only form that works adequately for them, reporting that they simply do not feel as well when they take levothyroxine or liothyronine alone. Our pharmacy can blend T4 and T3 pure powders in a specific ratio by as prescribed by your doctor. Commercially available tablets contain fillers and excipients that may not be tolerated by all patients. When we compound customized dosages, we have the ability to omit any problem-causing inactive ingredients and substitute non-reactive fillers.
When the medications that are commercially available aren’t right for you, we can work with your doctor and prepare slow-release capsules of levothyroxine (T4) and liothyronine (T3) in any strength. Harbor Compounding can assist in monitoring the effectiveness of your therapy and adjust your medication as directed by your doctor, to assure optimal results. Our highly trained compounding pharmacists are available to discuss individualized prescriptions, thyroid conversions, and all other considerations in therapy options.