The updated guidelines on hypothyroidism issued by the ATA in 2014 maintain the recommendation of levothyroxine as the standard of care for treating hypothyroidism, with the following considerations:
If levothyroxine dose requirements are much higher than expected, consider evaluating for gastrointestinal disorders such as Helicobacter pylori–related gastritis, atrophic gastritis, or celiac disease. If such disorders are detected and effectively treated, reevaluation of thyroid function and levothyroxine dosage is recommended.
Initiation or discontinuation of estrogen and androgen therapy should be followed by reassessment of serum TSH level at steady state because these medications may alter the levothyroxine requirement.
Serum TSH level should be reassessed upon initiation of agents such as tyrosine kinase inhibitors that affect thyroxine metabolism and thyroxine or triiodothyronine deiodination.
Serum TSH level monitoring is advisable when medications such as phenobarbital, phenytoin, carbamazepine, rifampin, and sertraline are started.
When deciding on a starting dose of levothyroxine, the patient’s weight, lean body mass, pregnancy status, etiology of hypothyroidism, degree of TSH elevation, age, and general clinical context, including the presence of cardiac disease, should be considered. The goal serum TSH level appropriate for the clinical situation should also be considered.
Thyroid hormone therapy should be initiated as an initial full replacement or as partial replacement with gradual increments in the dose titrated upward using the goal serum TSH level.
Dose adjustments should be made upon significant changes in body weight, with aging, and with pregnancy; TSH assessment should be performed 4-6 weeks after any dosage change.
Reference ranges of serum TSH levels are higher in older populations (eg, > 65 years), so higher serum TSH level targets may be appropriate.
Read more on the treatment of hypothyroidism.
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Cite this: Romesh Khardori. Fast Five Quiz: Key Aspects of Hypothyroidism - Medscape - Apr 15, 2019.