How often should I take KI?

A single dose of KI protects the thyroid gland for 24 hours. A one-time dose at the levels recommended in this fact sheet is usually all that is needed to protect the thyroid gland. In some cases, radioactive iodine might be in the environment for more than 24 hours. If that happens, local emergency management or public health officials may tell you to take one dose of KI every 24 hours for a few days. You should do this only on the advice of emergency management officials, public health officials, or your doctor. Avoid repeat dosing with KI for pregnant and breastfeeding women and newborn infants. Those individuals may need to be evacuated until levels of radioactive iodine in the environment fall.

Taking a higher dose of KI, or taking KI more often than recommended, does not offer more protection and can cause severe illness or death.

You should not take KI if:

  • You know you are allergic to iodine If you are unsure about this, consult your doctor. A seafood or shellfish allergy does not necessarily mean that you are allergic to iodine).
  • You have certain skin disorders (such as dermatitis herpetiformis or urticarial vasculitis).
  • People with thyroid disease (for example, multi-nodular goiter, Graves' disease, or autoimmune thyroiditis) may be treated with KI. This should happen under careful supervision of a doctor, especially if dosing lasts for more than a few days.

In all cases, talk to your doctor if you are not sure whether to take 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?