This episode of Drug Cards Daily is on the drug levothyroxine.

Levothyroxine has many brand names such as Synthroid, and Tirosint (to name a few). 

It is used as first-line therapy in hypothyroidism. It is also used in the treatment of thyrotropin-stimulating hormone (TSH) dependent thyroid cancers.

The main dosage form is tablets and it comes in a wide variety of strengths commonly dosed in micrograms (mcg).

Dosing is individualized with a general standard of either approximately 1-1.6 mcg/kg/day or 50 mcg/day. 

After initiation adjustments are made in 12-25 mcg increments every 3-6 weeks until serum TSH and T4 is at a normal range for greater than 5-6 weeks.

It is recommended to be taken in the morning 30-60 minutes before food.

If needed it can be crushed but levothyroxine should not be administered within 4 hours of calcium or iron containing products.