Final answer:
Antithyroid drugs like PTU are used to treat Grave's disease by inhibiting thyroid hormone production, while radioactive iodine is used in the treatment of thyroid cancer by exploiting the thyroid cells' ability to concentrate iodine. In contrast, hypothyroidism is managed with thyroid hormone supplements.
Step-by-step explanation:
Antithyroid drugs, such as Propylthiouracil (PTU), play a critical role in the management of Grave's disease, which is a form of hyperthyroidism where the thyroid gland overproduces hormones. These drugs function by limiting the thyroid gland's hormone production through various mechanisms. For example, some antithyroid drugs inhibit iodine uptake by the thyroid gland, substances like thiocyanate, perchlorate, and ouabain fall into this category. Others, like thiourea and thiouracil, block the enzyme thyroperoxidase, which is crucial for the synthesis of thyroid hormones. These medications effectively reduce the symptoms of hyperthyroidism and bring hormone levels closer to normal.
In contrast, when dealing with thyroid cancer, radiopharmaceuticals such as radioactive iodine (I-131) are utilized. These therapies rely on the thyroid cells' natural propensity to concentrate iodine, which is significantly heightened in cancerous thyroid cells. This approach allows for targeted destruction of abnormal tissue while sparing the rest of the body as much as possible. However, this treatment can cause a significant dose to organs responsible for the elimination process like the liver, kidneys, and bladder, posing a risk of damage to these organs.
In hypothyroidism, where the thyroid gland underproduces hormones, patients are usually treated with thyroid hormone supplements to restore normal levels. Unlike treatments for hyperthyroidism and cancer, these supplements simply provide the thyroid hormone that the patient's gland is not able to produce sufficiently.