Synthroid and Levothroid are used to treat which condition?

• A. Hyperthyroidism
• B. Hypothyroidism
• C. Cushing's syndrome
• D. Addison's disease

Answer: (B)

Synthroid and Levothroid are thyroid hormone replacement medications. They contain levothyroxine, a synthetic form of thyroxine (T4) that the body converts to the active hormone T3. When the thyroid doesn’t produce enough hormone, as in hypothyroidism, metabolism slows and people can experience fatigue, weight gain, cold intolerance, dry skin, and slowed heart rate. Supplying levothyroxine restores normal hormone levels, rebalances metabolic processes, and relieves these symptoms, bringing thyroid-stimulating hormone (TSH) and free T4 into the normal range.

They aren’t used for hyperthyroidism, which is excess thyroid hormone and is treated with methods to reduce production or block effects, nor for Cushing's syndrome or Addison's disease, which involve cortisol/adrenal hormone problems and require different treatments. Dosing of these medications is individualized and monitored with blood tests to ensure the right amount is being supplied. Taking them on an empty stomach and avoiding certain supplements or foods that can interfere with absorption helps keep treatment effective.