Antithyroid agents are medications used to treat conditions related to an overactive thyroid, such as Graves' disease. These drugs work by inhibiting the production of thyroid hormones, helping to restore normal hormone levels in the body. Common antithyroid agents include methimazole and propylthiouracil. These medications can help alleviate symptoms like rapid heartbeat, weight loss, and anxiety associated with hyperthyroidism. Treatment with antithyroid agents is often part of a broader management plan that may include radioactive iodine therapy or surgery for some patients, depending on the severity of their condition.