Literature review current through: Jan 2016. This topic last updated: Thu Apr 23 00:00:The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment.
More information about levothyroxine is in the web site section titled ". Know Your Pills. " The American Thyroid Association Guidelines (2009) have more information and recommendations. They are linked from the web site in the sections titled Newly Diagnosed and Thyroid Cancer Types.
INTRODUCTION The efficacy of thyroid hormone suppressive therapy in euthyroid patients with solitary benign thyroid nodules or sporadic nontoxic multinodular goiters is controversial. Most studies have shown that few thyroid nodules regress in patients taking thyroid hormone.
TSH in Initial Management and Long-Term Management. The American Thyroid Association's Guidelines (2009) make several recommendations regarding TSH. For initial TSH suppression, for high-risk and intermediate-risk patients, the guidelines recommend initial TSH below 0.1 mU/L, and, for low-risk patients TSH at or slightly below the lower limit of normal ( mU/L).
The T4 suppression dose for patients with thyroid cancer was more than 3 micrograms/kg lean body mass or 2 micrograms/kg body weight, whereas approximately 30 of non-toxic nodular goitre patients required less than 3 micrograms/kg lean body mass.
We, therefore, infer that residual thyroidal secretion in the patients with hypothyroidism due to benign causes is relatively independent of TSH stimulation. Further subdivision of patients with benign hypothyroidism revealed that patients with Graves' who developed hypothyroidism after 131I treatment showed a lower mean dose requirement than patients with spontaneous hypothyroidism.
(Recommendation 40). For long-term management, the guidelines recommend (Recommendation 49 In patients with persistent disease, the serum TSH should be maintained below 0.1mUL indefinitely in the absence of specific contraindications. In patients who are clinically and biochemically free of disease but who presented with high risk disease, consideration should be given to maintaining TSH suppressive.
Only the IV dosage form should be used for this condition : IV : -Initial loading dose: 300 to 500 mcg IV -Maintenance dose: 50 and 100 mcg IV, until the patient can tolerate oral therapy.
The result is diffuse and later multinodular thyroid enlargement; some nodules eventually become autonomous 3, and others may undergo cystic degeneration. Because thyroid hormone is presumed to reduce goiter size by reducing TSH secretion, suppressive therapy would be expected to be ineffective in patients in whom serum TSH concentrations were already subnormal due to autonomous.
-The peak therapeutic effect of this drug may not be attained for 4 to 6 weeks. Usual Pediatric Dose for Hypothyroidism CONGENITAL OR ACQUIRED HYPOTHYROIDISM : -Neonatal: 10 to 15 mcg/kg/day; if patient is at risk for development of cardiac failure, begin with a lower dose.
Patients whose thyroid glands have been removed will need to be on levothyroxine medication for the rest of their lives. The medication, which is necessary for maintaining a person's full health, must be taken on an empty stomach.
In patients free of disease, especially those at low risk for recurrence, the serum TSH may be kept within the low normal range (0.32mUL). In patients who have not undergone remnant ablation who are clinically free of disease and have undetectable suppressed serum Tg and normal neck ultrasound, the serum TSH may be allowed to.
Comments : -The dose should be individualized on the basis of clinical response and biochemical tests. Regular monitoring of TSH and thyroxine is recommended when starting therapy or changing the dose.
Generally, TSH is suppressed to less than 0.1 international units per liter (mU/L and this usually requires a dose of greater than 2 mcg/kg/day. However, in patients with high-risk tumors, the target level for TSH suppression may be less than 0.01 mU/L.
We have compared the dose of levothyroxine (L-T4) required to suppress serum TSH to given levels in two clinical groups: 1) 44 patients with thyroid cancer whose thyroid glands had been ablated by surgical thyroidectomy and 131I treatment, and 2) 113 patients with thyroidal failure due either to spontaneous primary hypothyroidism (31 patients) or after.
Therefore, the dose of this drug used for TSH suppression should be individualized based on the specific disease and the patient being treated. -In the treatment of well differentiated (papillary and follicular) thyroid cancer, this drug is used as an adjunct to surgery and radioiodine therapy.