American Thyroid Association Quick-Reference GUIDELINES Apps
Issue link: https://eguideline.guidelinecentral.com/i/521958
2 Treatment Î Because co-administration of food and levothyroxine is likely to impair levothyroxine absorption, the ATA recommends that, if possible, levothyroxine be consistently taken either 60 minutes before breakfast or at bedtime (3 or more hours after the evening meal) for optimal, consistent absorption. (W-M) Î The ATA recommends that, where feasible, levothyroxine should be separated from other potentially interfering medications and supplements (e.g., calcium carbonate and ferrous sulfate [See Table 2]). A 4-hour separation is traditional but untested. (W-L) Note: Other medications (e.g., aluminum hydroxide and sucralfate) may have similar effects but have been insufficiently studied. Î In patients in whom levothyroxine dose requirements are much higher than expected, evaluation for gastrointestinal disorders such as Helicobacter pylori–related gastritis, atrophic gastritis, or celiac disease should be considered. Furthermore, if such disorders are detected and effectively treated, re-evaluation of thyroid function and levothyroxine dosage is recommended. (S-M) Î Initiation or discontinuation of estrogen and androgens should be followed by reassessment of serum TSH at steady state since such medications may alter the levothyroxine requirement. Serum TSH should also be reassessed in patients who are started on agents such as tyrosine kinase inhibitors that affect thyroxine metabolism and thyroxine or triiodothyronine deiodination (See Table 2). (S-L). Note: Serum TSH monitoring is also advisable when medications such as phenobarbital, phenytoin, carbamazepine, rifampin, and sertraline are started. Î 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 all be considered. In addition, the serum TSH goal appropriate for the clinical situation should also be considered. (S-M) Î Thyroid hormone therapy should be initiated as an initial full replacement or as partial replacement with gradual increments in the dose titrated upward using serum TSH as the goal. Dose adjustments should be made when there are large changes in body weight, with aging, and with pregnancy, with TSH assessment 4-6 weeks after any dosage change. (S-M) Î The deleterious health effects of iatrogenic thyrotoxicosis include atrial fibrillation and osteoporosis. Because of these effects, the ATA recommends avoiding thyroid hormone excess and subnormal serum TSH values, particularly TSH values below 0.1 mIU/L, especially in older persons and postmenopausal women. (S-M)