This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Radioiodine

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

Radioactive iodine is selectively absorbed by, and destroys, functioning thyroid cells. It is administered as a tasteless, colourless liquid. It is difficult to predict the precise dose necessary for euthyroidism and so the amount given represents a best guess. Typical doses vary from 5-15 mCi depending upon the size of the gland. Some authorities recommend a very large dose to induce rapid hypothyroidism which is then corrected with thyroxine. A response is not detectable for 6-8 weeks during which time cover with carbimazole or a beta blocker is required. Carbimazole must be delayed for 2-3 days after taking radioactive iodine as it prevents iodine uptake.

Hyperthyroidism resolves in up to 60% of patients after a single dose of I-131. A second dose should be given if there is no improvement within about 4 months. About 8% per annum become hypothyroid in the first few years; permanent hypothyroidism is present in 80% by 20 years.


Related pages

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.