A class of drugs known as thionamides is mostly used to treat hyperthyroidism, a disorder marked by an overactive thyroid gland. By preventing the thyroid gland from producing excessive amounts of thyroid hormone, these medications help to restore normal hormone levels in the body. In clinical practice, methimazole and propylthiouracil (PTU) are the two major thionamides utilized. With a once-daily dosage and a longer duration of action, methimazole is the recommended thionamide. It functions by preventing the thyroid peroxidase enzyme from doing its job, which is essential for the production of thyroid hormones. Methimazole efficiently lowers the synthesis of the two primary thyroid hormones, triiodothyronine (T3) and thyroxine (T4), by inhibiting this enzyme.Another thionamide that prevents the formation of thyroid hormone is propylthiouracil (PTU). However, because of the increased risk of severe liver injury, it is used less frequently than methimazole. PTU is typically saved for patients who cannot take methimazole or for particular situations, as when a woman is pregnant and methimazole is not advised because of possible birth problems. The first-line treatment for hyperthyroidism is usually thionamides, particularly in individuals with toxic multinodular goiter, toxic adenoma, or Graves' disease. These drugs aid in the relief of hyperactive thyroid symptoms, including tremors, weight loss, heat intolerance, and an accelerated heart rate.Patients receiving thionamide therapy are frequently subjected to rigorous monitoring of their thyroid function, including routine blood tests to measure hormone levels. Restoring normal thyroid hormone levels without inducing hypothyroidism—a disorder in which the thyroid gland is underactive—is the aim of treatment. Despite being typically well-tolerated, thionamides may cause adverse reactions. Common adverse effects include joint discomfort, nausea, redness, and itching. Agranulocytosis, or a sharp decrease in white blood cells, hepatotoxicity, or damage to the liver, and vasculitis, or inflammation of the blood vessels, are more severe but uncommon adverse effects. Patients should be instructed to notify their healthcare physician right away if they have any unexpected symptoms.To sum up, thionamides like propylthiouracil and methimazole are crucial drugs for treating hyperthyroidism. They effectively manage symptoms related to an overactive thyroid by preventing the synthesis of thyroid hormones. To guarantee the best possible treatment for patients receiving thionamide medication, close observation and knowledge of possible adverse effects are essential components.