Thyroid hormones

Thyroid hormones replace the hormone the thyroid gland makes, restoring normal metabolism in hypothyroidism. Levothyroxine is taken once daily on an empty stomach, 30 to 60 minutes before breakfast. Doses are adjusted gradually based on TSH levels, and too high a dose causes signs of an overactive thyroid such as a racing heart, palpitations, and weight loss. Calcium, iron, and antacids reduce its absorption, so they are taken several hours apart from the dose.

• LevothyroxineKnown brand names include Synthroid, Levoxyl, Unithroid, Euthyrox, and Tirosint.