Propylthiouracil

Definition

Propylthiouracil is an antithyroid medication used to treat hyperthyroidism by inhibiting the synthesis of thyroid hormones. It is particularly effective in managing Graves' disease.

5 Must Know Facts For Your Next Test

1. Propylthiouracil inhibits the enzyme thyroid peroxidase, which is crucial for the production of thyroid hormones.
2. It is often preferred over methimazole during the first trimester of pregnancy due to a lower risk of teratogenic effects.
3. Common side effects include rash, nausea, and potential liver toxicity, making liver function monitoring essential.
4. Propylthiouracil can also inhibit peripheral conversion of T4 (thyroxine) to T3 (triiodothyronine), further reducing thyroid hormone levels.
5. Patients on propylthiouracil need regular monitoring of their complete blood count (CBC) due to the risk of agranulocytosis.

Review Questions

• What enzyme does propylthiouracil inhibit to reduce thyroid hormone production?
• Why might propylthiouracil be preferred over methimazole in early pregnancy?
• What are two critical side effects that require monitoring while a patient is on propylthiouracil?

Related terms

Methimazole: Another antithyroid drug used in treating hyperthyroidism but with different safety profiles during pregnancy.

Graves' Disease: An autoimmune disorder that leads to overactivity of the thyroid gland and is commonly treated with antithyroid drugs.

Thyroid Peroxidase: An enzyme in the thyroid gland essential for the production of thyroid hormones, targeted by propylthiouracil.