Potassium iodide (KI) is a type of iodine a person may receive during a radiation emergency. It works by preventing the thyroid from absorbing a type of radioactive material.

KI is a type of medical iodine salt. The thyroid can use iodine to produce thyroid hormones. In cases of radiation emergency, KI can block the thyroid gland from absorbing radiation, which can help prevent complications.

A person should not use KI unless public health officials, emergency response officials, or a healthcare professional advises them to do so. If using KI, a person should use the dosage a health expert recommends. This is because taking KI unnecessarily or incorrectly can have harmful health effects.

Read on to learn more about potassium iodide, including how it may help against radiation and its other uses.

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Potassium iodide is a type of iodine salt. It is commonly known as KI.

A doctor may recommend using KI during a radiation emergency because it can help prevent the harmful effects of certain types of radiation.

The thyroid is a butterfly-shaped gland in the neck. It produces hormones crucial to human health. To produce these hormones, the thyroid uses iodine from a person’s diet.

During a radiation emergency, there may be high levels of radioactive iodine in the environment, which the thyroid may absorb by mistake.

When a person uses KI appropriately, it can block the thyroid gland’s uptake of radioactive iodine. It does so by saturating the thyroid with stable iodine to continue producing hormones, which prevents it from absorbing radioactive iodine.

This can help reduce the risk of potential health complications, such as thyroid cancer, that could develop from exposure to radioactive iodine.

The main function of KI is to protect the thyroid from radioactive iodine.

Radioactive isotopes, including iodine-131, may be present in the atmosphere during a radiation emergency. If a person inhales or ingests these isotopes, they can accumulate in the thyroid and result in health problems.

KI works by saturating the thyroid with non-radioactive iodine. The thyroid absorbs iodine to produce hormones and cannot differentiate between stable and radioactive iodine.

By consuming KI, the thyroid becomes saturated with stable iodine. Since KI contains so much iodine, the thyroid becomes full and cannot absorb more iodine for the next 24 hours.

As such, KI prevents the thyroid from absorbing radioactive iodine, which reduces the risk of radiation-induced thyroid problems.

Health experts may advise using KI in the event of a nuclear power plant accident or a radiological emergency where radioactive iodine is present in the environment.

After such an event in the United States, a person should follow instructions from local public health or emergency management officials.

If an event occurs outside the country, it will likely not be necessary to take KI. However, scientists will track the environment for the presence of radioactive iodine and advise if people should start taking KI.

To be most effective, a person should take KI before or shortly after exposure to radioactive iodine. After administering KI, it will be effective for roughly 24 hours. After evacuating areas with radioactive iodine, it is not necessary to continue taking KI.

Additionally, a medical professional may use KI for treating conditions related to thyroid hormones. These uses may include:

The appropriate dose of KI may vary depending on various factors, including a person’s age, weight, and level of exposure.

Health authorities and government agencies will provide specific guidelines during nuclear emergencies. It is essential to follow these guidelines carefully to ensure safe and effective usage.

Currently, two forms of KI have approval from the Food and Drug Administration (FDA). They include tablets available in two strengths and an oral liquid solution available in one concentration.

The FDA recommends the following single doses of KI following radioactive exposure:

KI dose in milligrams (mg) Number of 130-mg tabletsNumber of 65-mg tabletsMilliliters (mL) of oral solution, 65 mg/mL
Adults over 40 years130 mg122 mL
Adults 18–40 years130 mg122 mL
Pregnant or lactating people130 mg122 mL
Teens 12–18 years65 mg1/211 mL
Children 3–12 years65 mg1/211 mL
Children 1 month to 3 years32 mguse oral solution1/20.5 mL
Infants from birth to 1 month16 mguse oral solutionuse oral solution0.25 mL

If an oral KI solution is not available, the FDA advises people can make an oral solution at home using KI tablets.

People who are allergic to iodine should not take KI. If a person is allergic to shellfish, has certain skin problems, or has certain thyroid problems, they can consult a doctor.

It is not advisable for a person to use KI as a supplement. Using KI unnecessarily can lead to adverse effects. A person should only use KI following advice from local public health officials, emergency management officials, or their doctor.

KI is not an anti-radiation drug. It is not a general radioprotective agent. It can only prevent the uptake of radioactive iodine into the thyroid gland following internal exposure.

KI does not protect a person from external radiation and does not prevent radioactive iodine from entering the body. Instead, KI prevents the accumulation of radioactive iodine in the thyroid.

Additionally, iodized table salt does not contain sufficient concentrations of iodine to block the uptake of radioactive iodine. Ingesting high amounts of iodized salt can cause health problems. As such, a person should not use iodized table salt as a substitute for KI.

When a person uses KI appropriately, it is generally safe and well tolerated, and side effects are rare.

The risk of side effects from KI increases with age. For this reason, some health experts may advise against adults ages 40 years and older from using KI.

However, the benefits of using KI as recommended during radiation emergencies typically far outweigh any potential risks.

Potential adverse effects of KI may include:

  • gastrointestinal problems
  • skin rashes
  • inflammation of the salivary glands
  • allergic reactions
  • hypothyroidism, or underactive thyroid
  • severe illness, which can be fatal

The FDA has approved KI as an over-the-counter (OTC) medication. As such, a person can purchase KI at pharmacies, health stores, or online retailers. However, it is crucial to ensure the product is FDA approved and meets safety standards.

Additionally, the U.S Nuclear Regulatory Commission notes that U.S. states that have populations within a 10-mile emergency planning zone of a nuclear power plant should consider including KI in emergency plans.

In accordance with FDA dosing guidelines, the commission can supply KI to populations within the emergency planning zone.

Potassium iodide is a compound that may safeguard the thyroid from radioactive iodine exposure. It works by blocking the absorption of radioactive iodine.

However, it is essential that a person follows KI dosing guidelines to avoid adverse effects. Additionally, unless a doctor advises, people should avoid using KI as a supplement due to these potential side effects.