levothyroxine sodium, Synthroid, Levoxyl, Levothroid, Unithroid, Tirosint, Levo-T

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GENERIC NAME: levothyroxine sodium

BRAND NAME: Synthroid, Levoxyl, Levothroid, Unithroid, Tirosint, Levo-T

DRUG CLASS AND MECHANISM: Levothyroxine is a synthetic (man-made) version of the principle thyroid hormone, thyroxine (T4) that is made and released by the thyroid gland. Thyroid hormone increases the metabolic rate of cells of all tissues in the body. In the fetus and newborn, thyroid hormone is important for the growth and development of all tissues including bones and the brain. In adults, thyroid hormone helps to maintain brain function, utilization of food, and body temperature, among other effects.

GENERIC AVAILABLE: Yes. Generic and branded tablets of levothyroxine may differ:

  • in the amount of levothyroxine they contain,
  • the absorption of the levothyroxine into the body, and
  • the distribution of levothyroxine throughout the body.

This means that ingestion of 1 mg of generic levothyroxine may not have the same effect on the body as 1 mg of another generic or branded levothyroxine. Practically speaking, this means that when changing between levothyroxine manufactured by different pharmaceutical companies, a change in dose may be necessary to maintain the desired effect or to prevent toxicity. When switching between brands or generics, it is important to ensure that both preparations are equivalent or to check blood thyroid levels weekly.

PRESCRIPTION: Yes.

PREPARATIONS:

  • Tablets: 0.025, 0.05, 0.075, 0.088, 0.1, 0.112, 0.125, 0.137, 0.15, 0.175, 0.2 and 0.3 mg.
  • Capsules: 0.013, 0.025, 0.05, 0.075, 0.088, 0.1, 0.125 and 0.15 mg.
  • Powder for intravenous injection: 200 mcg and 500 mcg per vial.
Medically Reviewed by a Doctor on 3/27/2013



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