Since I’ve been looking at the threat of a dirty bomb attack as a real, and having high probability of occurrence I thought I would look at what may be the only widely available medical treatment for radiation contamination to a human. Potassium Iodide, KI, is a salt, white in color that is widely available without prescription. Fairly inexpensive, many of the preparedness houses carry these tablets as part of their regular stock.

For instance, Emergency Essentials sells a package of 14 130mg tablets for $10.95 in their latest mailing. That is quite affordable considering the level of protection they provide, as long as you actually need that protection. But you don’t always need it in a radiological attack or event.

KI will only protect the Thyroid from radioactive Iodine, or more specifically, Iodine-131. There are other uses by way of medical treatments with KI, and many people should not take this substance for a number of reasons, so, even though it is available without a prescription you should consult a medical professional regarding your questions before stocking up on these tablets. There seems to be some idea floating around that KI will protect you in all radioactive fallout incidents. This is not the case as most events will probably not create the environment to allow for the generation of fissionable materials that would result in the fallout containing Iodine-131.

Nuclear reactor failures and high yield warheads are about the only situations where this situation will be the result. Dirty bombs and mislaid scrap product will not have any risk of Iodine-131, but they will have, or emit other equally dangerous radioactive elements. If a warning goes out indicating a radiation release from a reactor near you, you may be advised to take KI as a precaution.

Wanting to provide some acceptable facts, I copied these FAQs from the FDA The NRC and the CDC also provide their own FAQs, which are identical to these;

Frequently Asked Questions on Potassium Iodide (KI)

In December 2001, the Food and Drug Administration (FDA) issued a final Guidance on Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies1. The objective of the document is to provide guidance to other Federal agencies, including the Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission (NRC), and to state and local governments regarding the safe and effective use of potassium iodide (KI) as an adjunct to other public health protective measures in the event that radioactive iodine is released into the environment. The adoption and implementation of the recommendations are at the discretion of the state and local governments responsible for developing regional emergency-response plans related to radiation emergencies. The recommendations in the guidance address KI dosage and the projected radiation exposure at which the drug should be used. This guidance updates FDA’s 1982 recommendations.

1.  What does potassium iodide (KI) do?

The effectiveness of KI as a specific blocker of thyroid radioiodine uptake is well established. When administered in the recommended dose, KI is effective in reducing the risk of thyroid cancer in individuals or populations at risk for inhalation or ingestion of radioiodines. KI floods the thyroid with non-radioactive iodine and prevents the uptake of the radioactive molecules, which are subsequently excreted in the urine.

2.  Can potassium iodide (KI) be used to protect against radiation from bombs other than radioactive iodine?

Potassium iodide (KI) works only to prevent the thyroid from uptaking radioactive iodine. It is not a general radioprotective agent.

3.  Who really needs to take potassium iodide (KI) after a nuclear radiation release?

The FDA guidance prioritizes groups based on age, which primarily determines risk for radioiodine-induced thyroid cancer.  Those at highest risk are infants and children, as well as pregnant and nursing females, and the recommendation is to treat them at the lowest threshold (with respect to predicted radioactive dose to the thyroid).  Anyone over age 18 and up to age 40 should be treated at a slightly higher threshold.  Finally, anyone over 40 should be treated with KI only if the predicted exposure is high enough to destroy the thyroid and induce lifelong hypothyroidism (thyroid deficiency).

4.  What potassium iodide (KI) products are currently available? 

As of January 2005, Iosat, ThyroSafe, and ThyroShield are FDA approved KI products. You can find out more about these products at Drugs@FDA2. Please be aware that only the KI products approved by FDA may be legally marketed in the United States.

5.  How are these products available?

(This section lists sources that KI could be obtained from by the general public. Please visit FDA the site for the list. Not having checked these retailers for accuracy or viability as a competent source, I cannot vouch for them here. D.L. Soucy)

6.  What dosages of potassium iodide (KI) should be taken for specific exposure levels?

Exposures greater than 5 cGy:   
    Birth through 1 mo.  – 16 mg.
    1 mo. through 3 yrs.  – 32 mg.
    3 yrs through 18 yrs.  – 65 mg. (Adolescents>150 pounds should take adult dose.)

Exposures greater than 10 cGy: 
    18 yrs through 40 yrs. – 130 mg

Exposures greater than 500 cGy: 
    Adults over 40 yrs – 130 mg.

7.  How long should potassium iodide (KI) be taken?

Since KI protects for approximately 24 hours, it should be dosed daily until the risk no longer exists.  Priority with regard to evacuation and sheltering should be given to pregnant females and neonates because of the potential for KI to suppress thyroid function in the fetus and neonate.  Unless other protective measures are not available, we do not recommend repeat dosing in pregnant females and neonates.

8.  Who should not take potassium iodide (KI) or have restricted use?

Persons with known iodine sensitivity should avoid KI, as should individuals with dermatitis herpetiformis and hypocomplementemic vasculitis, extremely rare conditions associated with an increased risk of iodine hypersensitivity. Individuals with multinodular goiter, Graves’ disease, and autoimmune thyroiditis should be treated with caution — especially if dosing extends beyond a few days.

9.  What are the possible risks and side effects of taking potassium iodide (KI)?

Thyroidal side effects of KI at recommended doses rarely occur in iodine-sufficient populations such as the U.S. As a rule, the risk of thyroidal side effects is related to dose and to the presence of underlying thyroid disease (e.g., goiter, thyroiditis, Graves’).  FDA recommends adherence to the Guidance on Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies7 for intervention threshold and dose, though we recognize that the exigencies of any particular emergency situation may mandate deviations from those recommendations. With that in mind, it should be understood that as a general rule, the risks of KI are far outweighed by the benefits with regard to prevention of thyroid cancer in susceptible individuals.

10.  Should I check with my doctor first?

Potassium iodide (KI) is available over-the-counter (OTC).  However, if you have any health concerns or questions, you should check with your doctor.

11. As a doctor, should I be recommending potassium iodide (KI) for my patients who request it?

As with any drug, physicians should understand the risks and benefits of KI before recommending it or prescribing it to patients. We recommend that physicians read our guidance for more information. It is available on the FDA Drug Guidances8 web page, under procedural guidance #18. The FDA guidance discusses the rationale and methods of safe and effective use of KI in radiation emergencies. It specifically addresses threshold predicted thyroid radioiodine exposure for intervention and dosing by age group. The recommendations for intervention are based on categories of risk for thyroid cancer, with the young prioritized because of increased sensitivity to the carcinogenic effects of radioiodine.

12.  Should I go out and buy potassium iodide (KI) to keep on hand?

KI works best if used within 3-4 hours of exposure. Although FDA has not made specific recommendations for individual purchase or use of KI, the Nuclear Regulatory Commission has contracted to purchase KI for states with nuclear reactors and states that have population within the 10-mile emergency planning zone, e.g., Delaware or West Virginia.

13.  How do I know that potassium iodide (KI) will be available in case of an emergency?

FDA will continue to work with interested pharmaceutical manufacturers to assure that high quality, safe, and effective KI products are available for purchase by consumers, by state and local authorities, and by federal government agencies electing to do so.


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