Which medication is commonly used to treat hypothyroidism?

Which medication is commonly used to treat hypothyroidism?

• A. Methimazole
• B. Levothyroxine (Synthroid)
• C. Propylthiouracil
• D. Radioactive iodine

Answer: (C)

Hypothyroidism is treated with hormone replacement to restore normal thyroid hormone levels. Levothyroxine, a synthetic form of T4, is the standard drug for this purpose. It mimics the body's natural thyroid hormone and is preferred because of its stable effect, once-daily dosing, and ability to be precisely titrated. Treatment is guided by monitoring thyroid-stimulating hormone (TSH) and sometimes free T4 to keep levels within the reference range, which helps relieve symptoms like fatigue, cold intolerance, and weight changes. Dosing typically starts around 1.6 mcg/kg per day for healthy adults, but it’s adjusted for age, cardiovascular risk, and other health conditions. In pregnancy, the dose may need to be increased because physiological changes raise thyroid hormone requirements. The goal is symptom resolution plus a TSH in the target range. The other medications listed have different roles: methimazole and propylthiouracil inhibit thyroid hormone synthesis and are used to treat hyperthyroidism, not hypothyroidism. Radioactive iodine destroys thyroid tissue to reduce hormone production and is also used for hyperthyroidism or thyroid cancer risk, not as replacement therapy.

Hypothyroidism is treated with hormone replacement to restore normal thyroid hormone levels. Levothyroxine, a synthetic form of T4, is the standard drug for this purpose. It mimics the body's natural thyroid hormone and is preferred because of its stable effect, once-daily dosing, and ability to be precisely titrated. Treatment is guided by monitoring thyroid-stimulating hormone (TSH) and sometimes free T4 to keep levels within the reference range, which helps relieve symptoms like fatigue, cold intolerance, and weight changes.

Dosing typically starts around 1.6 mcg/kg per day for healthy adults, but it’s adjusted for age, cardiovascular risk, and other health conditions. In pregnancy, the dose may need to be increased because physiological changes raise thyroid hormone requirements. The goal is symptom resolution plus a TSH in the target range.

The other medications listed have different roles: methimazole and propylthiouracil inhibit thyroid hormone synthesis and are used to treat hyperthyroidism, not hypothyroidism. Radioactive iodine destroys thyroid tissue to reduce hormone production and is also used for hyperthyroidism or thyroid cancer risk, not as replacement therapy.