DRUG OF THE DAY: LEVOTHYROXINE

Levothyroxine is apparently the second most prescribed medication in the United States with 23.8 million prescriptions.

History: Levothyroxine was isolated in 1914 at the Mayo Clinic and then synthesized by British chemists in 1927.  

Brand names: Synthroid, Levothyroid, Levoxyl, Unithryoid

How it works:  Levothyroxine (T4) is a synthetic form of thyroxine, an endogenous hormone secreted by the thyroid gland. T4 is converted to its active metabolite, L-triiodothyronine (T3). Thyroid hormones (T4 and T3) then bind to thyroid receptor proteins in the cell nucleus and exert metabolic effects through control of DNA transcription and protein synthesis; involved in normal metabolism, growth, and development; promotes gluconeogenesis, increases utilization and mobilization of glycogen stores, and stimulates protein synthesis, increases basal metabolic rate (source: UptoDate)

Used for:  Hypothyrodism and pituitary thyrotropin-stiumulating hormone suppression

Cautions: Can cause heart palpitations, nausea, anxiousness, abdominal pain, weight loss, insomnia, increased appetite

Food interactions: Levothyroxine should be taken in the morning on an empty stomach thirty minutes before food.  Some foods interact with the binding of levothyroxine and can affect absorption (iron, calcium supplements).