Methods of Prevention

The thyroid gland in the neck is one of the most sensitive organs in the body to radiation. The thyroid uses iodine normally to make thyroid hormone. The radiation from a nuclear event releases radioactive iodine into the air. Exposure to high levels of radiation — as occurs during a nuclear plant meltdown — can lead to thyroid cancer. Radiation seeps into the body through skin and by breathing it into the lungs. It then travels to the thyroid unless potassium iodide is present to block it.

So how does potassium iodide help?

Taking potassium iodide pills temporarily stops the thyroid. If taken prior to radiation exposure, the iodine pills counter the effect of the radioactive iodine on the thyroid. This helps prevent the development of thyroid cancer down the road. For optimal protection against inhaled radioiodines, KI should be administered before the passage of the radioactive iodine plume, though KI may still have a substantial protective effect even if taken 3 or 4 hours after exposure. Take one dose as soon as possible and then every 24 hours at the same time each day.

In 1982, the U.S. Food and Drug Administration (FDA) approved potassium iodide to protect thyroid glands from radioactive iodine involving accidents or fission emergencies. Usually, only one dose of potassium iodide is needed since a single dose protects the thyroid gland for 24 hours. U.S. FDA-approved dosing of potassium iodide for this purpose is as follows (per 24 hours):

However, some sources recommend alternative dosing regimens. The above dosage is also recommended by WHO. Side effects are unlikely when KI is used at the recommended dose and for a short time. However, some of the possible side effects are skin rashes, swelling of the salivary glands, “Iodism” (metallic taste, burning mouth and throat, sore teeth and gums, symptoms of a head cold, and sometimes upset stomach and diarrhea) and an allergic reaction towards iodine.

Pregnant women should take it for their own protection and for that of the fetus, as iodine readily crosses the placenta. However, because of the risk of blocking fetal thyroid function with excess stable iodine, repeat dosing with KI of pregnant women should be avoided. Lactating females should be take it for their own protection to reduce the radioiodine content of the breast milk, but not as a means to deliver KI to infants, who should get their KI directly.