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Propylthiouracil

Indications and Usage

This drug is useful to decrease the thyroid's retention of radioiodine and may be considered if it is too late for KI (potassium iodide) to be effective.
Suggested PO dosing
- 100 mg (2 tabs, 50 mg/tab) PO tid
- Can be given daily for 8 days.

FDA Product Safety Info

Not FDA approved for this indication/off-label use
When KI is unavailable or contraindicated, propylthiouracil and methimazole may be considered alternative drugs for blocking thyroid uptake of radioiodine. However, propylthiouracil is not FDA-approved as a substitute for KI, and it should be used only in the case of documented and serious internal contamination with radioiodine when KI is unavailable or unlikely to be effective.
Propylthiouracil should not be used unless a health physicist has documented the expected thyroid radiation dose.
For adults over 40 years of age, treatment for radioiodine inhalation is not recommended unless the projected thyroid dose exceeds 500 rem.
The potential for granulocytopenia and agranulocytosis is significant.
WARNING: Pregnancy Category D

Management of Persons Contaminated with Radionuclides: Handbook (NCRP Report No. 161, Vol. I), National Council on Radiation Protection and Measurements, Bethesda, MD, 2008, Medical Treatments Arranged by Radionuclide (p. 215) and Table 12.15 (pp. 216-217). [Note: NCRP 161 supersedes NCRP 65.]