Chapter 15 · Nuclear and radiological emergency
15.9 Potassium iodide (KI)
Potassium iodide is one of the most misunderstood things in nuclear emergencies.
| What it DOES do What it does NOT do | |
|---|---|
| • Fills the thyroid with stable iodine so it does not absorb radioactive iodine. • Protects for about 24 hours per dose. • Most useful in nuclear power plant accidents, where radioactive iodine is more common (CDC). • Works best if taken within the 24 hours before or up to 4 hours after exposure (CDC). | • It is not a general radiation protectant (FDA). • It only protects the thyroid; it does not protect any other organ. • It does not protect against external radiation from fallout or against other radioactive materials, such as those in a dirty bomb. • It does not repair damage already done. |
- Take it only when public health or emergency authorities, or your doctor, tell you to, and follow their instructions. Do not take it "just in case" (FDA, CDC).
- Taking more than directed or more often does not protect more and can cause serious illness or death (FDA).
- The priority is babies, children, pregnant women, and breastfeeding women. Adults over 40 should take it only if authorities say so (CDC, FDA).
- Do not use it if you have a known sensitivity to iodine, and check with your doctor first if you have thyroid or heart disease. The dose is on the label of the FDA-approved product; follow it.
- Do not substitute KI with iodized salt, iodine-containing foods, iodine supplements, or iodine tincture: they do not protect and can cause harm (CDC).
- After a detonation, do not go out looking for KI. The main danger is external radiation from fallout, against which KI does nothing; going out exposes you more (CDC).
