Who should take KI?

The thyroid glands of a fetus and of an infant are most at risk of injury from radioactive iodine. Young children and people with low stores of iodine in their thyroid are also at risk of thyroid injury.

  • Infant (including breast-fed infants): Infants need to be given the recommended dosage of KI for babies. The amount of KI that gets into breast milk is not enough to protect breast-fed infants from exposure to radioactive iodine. The proper dose of KI given to a nursing infant will help protect it from radioactive iodine that it breathes in or drinks in breast milk.
  • Children: The United States Food and Drug Administration (FDA) recommends that all children internally contaminated with, (or likely to be internally contaminated with) radioactive iodine take KI, unless they have known allergies to iodine. Children from newborn to 17 years of age are the most sensitive to the potentially harmful effects of radioactive iodine.
  • Young Adults: The FDA recommends that young adults (between the ages of 18 and 40 years) internally contaminated with (or likely to be internally contaminated with) radioactive iodine take the recommended dose of KI. Young adults are less sensitive to the effects of radioactive iodine than are children.
  • Pregnant Women: Because all forms of iodine cross the placenta, pregnant women should take KI to protect the growing fetus. However, pregnant women should take only one dose of KI following internal contamination with (or likely internal contamination with) radioactive iodine.
  • Breastfeeding Women: Women who are breastfeeding should take only one dose of KI if they have been internally contaminated with (or are likely to be internally contaminated with) radioactive iodine. Because radioactive iodine quickly gets into breast milk, CDC recommends that women who are internally contaminated with (or are likely to be internally contaminated with) radioactive iodine, stop breastfeeding and feed their child baby formula or other food if it is available. If breast milk is the only food available for an infant, nursing should continue.
  • Adults: Adults older than 40 years should not take KI unless public health or emergency management officials say that contamination with a very large dose of radioactive iodine is expected. Adults older than 40 years have the lowest chance of developing thyroid cancer or thyroid injury after contamination with radioactive iodine. They also have a greater chance of having allergic reactions to KI.

Show All Answers

1. What is Potassium Iodide (KI)?
2. What does KI do?
3. How does KI work?
4. How well does KI work?
5. Who should take KI?
6. When should I take KI?
7. How much KI should I take?
8. How often should I take KI?
9. What are the possible risks and side effects of KI?
10. Where can I get KI?