PROPYLTHIOURACIL (Antithyroid Medication)

Indications: hyperthyroidism; thyrotoxicosis

Contraindications: hypersensitivity to drug; hepatic function impairment

Dental aspects: agranulocytosis; bone marrow depressant effects leading to increased risk of infections, delayed wound healing, gingival bleeding. If severe leukopenia or thrombocytopenia present, delay dental work until blood counts are returned to normal. Neuropathy also present (numbness of fingers, face). Close monitoring of blood counts required during therapy.

Side Effects (symptoms of overdose): coldness of skin; constipation; dry, puffy skin; tiredness; weakness; weight gain; loss of taste.

Mechanism: inhibits synthesis of thyroid hormone in thyroid gland by acting as substrate for thyroid peroxidase, which catalyzes incorporation of oxidized iodide into thyroglobulin. Does not interfere with action of thyroid on peripheral tissues, or inhibit release from thyroid gland.

Category: Pharmacology Notes