According to the CDC, KI (potassium iodide) is a salt of stable (not radioactive) iodine that can help block radioactive iodine from being absorbed by the thyroid gland, thus protecting this gland from radiation injury.
The thyroid gland is the part of the body that is most sensitive to radioactive iodine. KI (potassium iodide) is available without a prescription. Radioiodine can be released if there is a nuclear reactor accident, and anyone living within a 10-mile radius of a nuclear power plant should strongly consider potassium iodide tablets as part of your survival kit.
People should take KI (potassium iodide) only on the advice of public health or emergency management officials. There can be health risks associated with taking KI.
KI (potassium iodide) cannot protect the body from radioactive elements other than radioactive iodine. If radioactive iodine is not present, taking KI is not protective and could cause harm (CDC, 2015).
Radioactive iodine is not always a result of a nuclear explosion nor is it typically in a suitcase dirty bomb, testing would be required, however. The biggest threat is a terrorist attack on a nuclear power plant that would undoubtedly release radioactive iodine. States are and have been considering stockpiling tablets so they can be issued in the event of a nuclear accident. However, the tablets must be taken before the thyroid gland has absorbed the radioactive fallout. You can obtain the pills without a prescription so there is no point in waiting for your local government to decide on their issuance.
Preventing exposure is, of course, the best remedy and those outside of the fallout range will probably not need the medication. There are steps to take immediately after a detonation or power plant accident. If you know of or suspect an incident has occurred then take the needed action without being told by the local authorities. Limiting exposure time is critical.
Follow the label directions carefully for children and for adults with underlying medical conditions.
If you are iodine sensitive, you should avoid KI. Those with dermatitis herpetiformis and hypocomplementemia vasculitis, which are extremely rare conditions associated with an increased risk of iodine hypersensitivity should not take the medication. No one with nodular thyroid with heart disease should take KI. Individuals with multinodular goiter, Graves’ disease, and autoimmune thyroiditis should be treated with caution, in particular, if dosing extends beyond a few days.
CDC. (2015). Retrieved 2016, from https://emergency.cdc.gov/radiation/ki.asp