Propylthiouracil(PTU)

Structure

• Propylthiouracil is an antithyroid drug with a thiouracil structure, featuring a propyl side chain attached to the uracil ring.

• Chemical Formula: C₅H₉N₃O₂S

Propylthiouracil (PTU)

Mode of Action

• Thyroid Hormone Synthesis Inhibition: Blocks the enzyme thyroid peroxidase, preventing the iodination of tyrosine residues and coupling of iodotyrosines to form T3 and T4.

• Iodine Organification Inhibition: Disrupts the incorporation of iodine into thyroid hormones.

• Peripheral Conversion Inhibition: Reduces peripheral conversion of T4 to the more active T3 form.

Uses

• Hyperthyroidism: Treats Graves' disease and toxic multinodular goiter by reducing thyroid hormone production.

• Thyroid Storm: Emergency treatment of life-threatening hyperthyroidism with severe systemic effects.

• Preparation for Thyroid Surgery/Radiation: Lowers thyroid hormone levels prior to radioactive iodine therapy or surgical intervention.

• Thyroid Cancer: Used in some cases to manage thyroid hormone levels during treatment.

Side Effects of Propylthiouracil

• Agranulocytosis: Severe decrease in white blood cells, increasing infection risk.

• Hepatotoxicity: Liver damage and dysfunction.

• Rash and Allergic Reactions: Skin rashes, itching, and other hypersensitivity responses.

• Nausea and Vomiting: Gastrointestinal disturbances are common.

• Joint Pain: Arthralgia and myalgia may occur.