Hypothyroidism medical therapy

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Medical Therapy

Pharmacotherapy

Main article: Medical use of thyroid hormones

Both synthetic and animal-derived thyroid tablets are available and can be prescribed for patients in need of additional thyroid hormone. Thyroid hormone is taken daily, and doctors can monitor blood levels to help assure proper dosaging.

The American Thyroid Association cautions against taking herbal remedies, and warns that taking too much iodine can actually worsen hypothyroidism.

T₄ - T₃ combination therapy

Clinical practice guidelines by the American Thyroid Association in 2014 state:

• "we recommend against the routine use of combination treatment"
• "For patients with primary hypothyroidism who feel unwell on levothyroxine therapy alone (in the absence of an allergy to levothyroxine constituents or an abnormal serum thyrotopin), there is currently insufficient evidence to support the routine use of a trial of a combination of levothyroxine and liothyronine therapy outside a formal clinical trial or N-of-1 trials"
• "genetic testing is not recommended as a guide to selecting therapy"

Regarding underlying evidence, meta-analysis in 2006 of 11 randomized controlled trials found no advantage with the T₄ - T₃ combination therapy over the T₄ monotherapy.

One view of this meta-analysis is that many of the studies involved were not properly designed. They tested the medication's effectiveness by providing the same dose of thyroid medication to each patient and by utilizing the TSH test as a measure of treatment effectiveness. Thyroid medication must be individualized to the patient, carefully observing free T4 and free T3 (not TSH, which is a diagnostic tool but not a treatment tool). Beneficial effects would not expect to be seen at doses not tailored to the individual's needs. Clinically, most physicians prescribing T3 as part or all of a hypothyroid patient's treatment find that most patients receiving T3 in fact must be on a larger dose than was administered in these studies. The meta-analysis results ought to be held in question, therefore; and the knowledgeable physician will administer T3 medication for the hypothyroid patient who continues to present with symptoms and whose free T3 level is low, or low in the range.

Subclinical hypothyroidism

A meta-analysis by the Cochrane Collaboration found no benefit except "some parameters of lipid profiles and left ventricular function".