Propylthiouracil (PTU)
Propylthiouracil (PTU) is a pill that lowers thyroid hormone output in an overactive thyroid. The drug blocks the enzyme that adds iodine to thyroid hormone. PTU also slows the change of T4 into T3, the active form.
The second action matters. Most T3 is made outside the thyroid, when the liver and the kidneys change T4.1 Other drugs slow that change and lower T3.2
Thyroid levels shape cycles, ovulation, and early pregnancy. Clinicians watch TSH and thyroid hormone closely when a woman on PTU is trying to conceive.
Cited in this entry
- Kelly GS. Peripheral metabolism of thyroid hormones: a review. Alternative Medicine Review : a Journal of Clinical Therapeutic. 2000. https://rrmacademy.org/library/peripheral-metabolism-of-thyroid-hormones-a-review-recaxvxkumcn2mog6/
- Robbins J. Factors altering thyroid hormone metabolism. Environmental Health Perspectives. 1981. https://pubmed.ncbi.nlm.nih.gov/7238448/
This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.
