Antithyroid agent

Antithyroid agents are a group of medications used primarily in the treatment of hyperthyroidism, a condition characterized by an overactive thyroid gland. These agents work by reducing the production and release of thyroid hormones in the body.

Mechanism of Action

Antithyroid agents function by inhibiting the enzyme thyroid peroxidase, which plays a crucial role in the synthesis of thyroid hormones. By blocking this enzyme, these medications prevent the iodination of tyrosine residues in thyroglobulin, thereby reducing the production of thyroxine (T4) and triiodothyronine (T3), the two primary thyroid hormones.

Types of Antithyroid Agents

There are two main types of antithyroid agents: thionamides and iodides.

Thionamides

Thionamides, such as propylthiouracil and methimazole, are the most commonly used antithyroid agents. They inhibit the synthesis of thyroid hormones and also have an immunosuppressive effect, which can be beneficial in the treatment of Graves' disease, an autoimmune disorder that is a common cause of hyperthyroidism.

Iodides

Iodides, including potassium iodide and sodium iodide, inhibit the release of thyroid hormones into the bloodstream. They are often used in preparation for thyroid surgery to reduce the vascularity of the thyroid gland and decrease the risk of bleeding.

Side Effects

Like all medications, antithyroid agents can cause side effects. These may include skin rash, hepatitis, neutropenia, and, in rare cases, agranulocytosis. Regular monitoring of blood counts and liver function is recommended for patients taking these medications.

See Also

• Hyperthyroidism
• Thyroid hormones
• Thyroid gland
• Graves' disease

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