Use of Levothyroxine in Hospitalized Patients
Initiation or adjustment of oral levothyroxine therapy should be considered in noncritically ill hospitalized patients with pre-existing hypothyroidism, according to the American Thyroid Association (ATA) guidelines. The patients should be evaluated for the possibility of adrenal insufficiency before beginning levothyroxine therapy. The goal of treatment should be long-term normalization of serum thyroid-stimulating hormone (TSH) when steady state thyroid hormone levels are achieved.
While oral levothyroxine is recommended in these patients, the enteral route can be used if oral therapy is not feasible. In addition, intravenous administration (75% of oral dose) can be used if the patient cannot tolerate the enteral route.
Treatment for Patients With Myxedema Coma
The ATA recommends that patients with myxedema coma should first receive empiric glucocorticoid coverage with intravenous glucocorticoid administration (at doses appropriate for the stressed state). Next, these patients should be given a loading intravenous dose of 200 to 400 mcg of levothyroxine, with lower doses given for patients who are of smaller stature, older, or who have a history of coronary disease or arrhythmia. Thereafter, a daily dose of 1.6 mcg/kg body weight, reduced to 75% in patients given intravenous administration, should be given.
The therapeutic endpoints of levothyroxine therapy in patients with myxedema coma should be improved mental status, improved cardiac function, and improved pulmonary function. Thyroid hormones may be measured every 1 to 2 days. It is unclear what the optimal levels for serum TSH and thyroid hormones should be in this population. However, high serum triiodothyronine levels may indicate the need to decrease the dose. Likewise, an increase in dose or addition of liothyronine could be considered in patients who fail to respond to levothyroxine therapy.
An initial liothyronine dose of 5 to 20 mcg may be given, followed by a maintenance dose of 2.5 to 10 mcg every 8 hours, in addition to levothyroxine therapy. As with liothyronine administration, lower doses of liothyronine should be given to patients who are of smaller stature, older, or who have a history of coronary disease or arrhythmia.
Non-Thyroidal Illness Syndrome
For hospitalized patients with critical illness exhibiting non-thyroidal illness syndrome, the ATA does not recommend use of levothroxine or liothyronine due to a lack of randomized controlled studies supporting this approach. In addition, levothroxine has been linked to safety issues.
Cardiac Dysfunction
In hospitalized patients with cardiac dysfunction (eg, advanced heart failure) and low serum triiodothyronine concentrations, the ATA does not recommend liothyronine treatment given the lack of long-term randomized trials in this population.
Thyroid Hormone Analogs
The ATA recommends against use of thyroid hormone analog or thyromimetic (ie, thyroid hormone analogs with specificity for TR-beta) therapy in euthyroid patients with non-hypothyroid–related medical conditions (eg, dyslipidemia) due to lack of evidence on benefits or side effects of this use.
In patients with genetic syndromes of resistance to thyroid hormone, the goals of therapy are to improve the symptoms caused by excessive TR-alpha signaling, while minimizing the symptoms caused by deficient TR-beta signaling. Use of the thyroid hormone analog triiodothyroacetic acid is not currently recommended for these patients with resistance to thyroid hormone due to lack of clinical research.
March 12, 2015
American Thyroid Association Hypothyroidism Guideline Summary Continues at:
Part I: American Thyroid Association Continues to Recommend Levothyroxine as First-Line Therapy for Hypothyroidism
Part II: American Thyroid Association Guideline for Treatment of Hypothyroidism
Part III: American Thyroid Association Guideline: Treatment of Hypothyroidism Other Than Levothyroxine Monotherapy
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