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Potassium Iodide – A Protective Measure Not a Magic Pill

Patricia Milligan
Senior Level Advisor

refresh leafOne of the protective measures that communities around nuclear power plants might use in the case of a radiological emergency is potassium iodide. But potassium iodide, often just called by its chemical symbol, KI, can be confusing for the public — exactly what does it do and when should it be taken?

So here are some facts about KI:

  • It is not an “anti radiation” pill. Potassium iodide is a salt, similar to table salt. It is routinely added to table salt to make it “iodized.” Potassium iodide, if taken within the appropriate time and at the appropriate dosage prevents the thyroid gland from taking in radioactive iodide. This can help to reduce the risk from thyroid disease, including cancer as a result of a severe reactor accident. KI doesn’t protect the thyroid gland from any other radioactive element nor does it protect the thyroid or the whole body from external exposure to radiation. Its use is very limited.
  • KI comes as a tablet, either in 65 mg or 130 mg strengths, and dose is administered according to age and/or weight. It is very important that FDA dosing guidelines be followed when taking or administering KI. Too much stable iodide in the form of KI can be harmful to small children. A tablet can be easily divided, crushed and mixed with liquid to make it easier to swallow for infants, small children and those who have difficulty swallowing.
  • It is important that KI not be taken unless directed by appropriate state or local authorities during the emergency and then, it should be taken in accordance with those directions.
  • KI is NOT the same thing as table salt, and table salt should never be ingested as a substitute.
  • The NRC provides KI – free of charge — to states that have requested it for their population within the 10-mile emergency planning zone of a nuclear power plant. Some states have distributed KI to residents of a plant’s emergency planning zone. In other states, KI is stockpiled and would be distributed if and when it is necessary.
  • In the event of a serious nuclear incident, KI could be used in addition to evacuation or sheltering in place in accordance with directions from responsible state/local officials. For more information, see Consideration of Potassium Iodide in Emergency Planning.

The FDA’s Frequently Asked Questions on KI is a very good resource if you want more information.

REFRESH is an occasional series where we revisit previous blog posts. This one originally ran in June 2012.

22 responses to “Potassium Iodide – A Protective Measure Not a Magic Pill

  1. Tanmay Mahajan April 30, 2015 at 7:15 am

    Nicely Written!

  2. valenciajoshua December 10, 2014 at 1:04 pm

    very good guidelines, especially pertinent to communities that leave near a nuclear plant. we have a nuclear plant in south africa and i am certainly going to share this in our facebook group incase there is ever a nuclear leakage

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