Levothyroxine is used to treat:

Choice A rationale Levothyroxine is a synthetic form of thyroxine (T4). It is the standard treatment for hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. The medication replaces the deficient hormone, restoring normal metabolic function in the body. Choice B rationale Levothyroxine is a thyroid hormone replacement, so it would worsen hyperthyroidism, a condition characterized by an overproduction of thyroid hormones. The treatment for hyperthyroidism involves anti-thyroid medications, radioactive iodine, or surgery to reduce hormone levels. Choice C rationale While levothyroxine is sometimes used after thyroid cancer surgery to suppress TSH (thyroid-stimulating hormone) and prevent the recurrence of cancer, its primary and most common use is to treat the resulting hypothyroidism, not the cancer itself. Choice D rationale Thyroiditis is inflammation of the thyroid gland. While it can cause temporary hyperthyroidism or hypothyroidism, levothyroxine is only used to treat the resulting hypothyroidism after the inflammatory phase has passed, not the inflammation itself.