Acute Radiation Syndrome (ARS), or radiation sickness, is a serious illness that can happen when a person is exposed to very high levels of radiation, usually over a short period of time. The amount of radiation that a person’s body absorbs is called the radiation dose.

People exposed to radiation will get ARS only if:

• The radiation dose was high
• The radiation was able to reach internal organs (penetrating)
• The person’s entire body, or most of it, received the dose
• The radiation was received in a short time, usually within minutes

Symptoms of ARS may include nausea, vomiting, headache, and diarrhea.

• These symptoms start within minutes to days after the exposure, can last for minutes up to several days, and may come and go.
• If you have these symptoms after a radiation emergency, seek medical attention as soon as emergency officials determine it is safe to do so.

After the initial symptoms, a person usually looks and feels healthy for a period of time, after which he or she will become sick again with variable symptoms and severity that vary depending on the radiation dose that he or she received.

• These symptoms include loss of appetite, fatigue, fever, nausea, vomiting, diarrhea, and possibly even seizures and coma.
• This seriously ill stage may last from a few hours up to several months.
• People who receive a high radiation dose also can have skin damage. This damage can start to show within a few hours after exposure or it may be delayed for several days. It can include swelling, itching, and redness of the skin (like a bad sunburn) or may be more severe and include blisters or ulcers.
  • The skin may heal for a short time, followed by the return of swelling, itching, and redness days or weeks later.
  • Complete healing of the skin may take from several weeks up to a few years.
  • The time for skin to heal depends on the radiation dose the person’s skin received.
  • People who receive a high radiation dose to all or part of the body also may experience temporary hair loss. It may take several weeks for the hair to grow back.

• Treatment of ARS focuses on reducing and treating infections, maintaining hydration, and treating injuries and burns. Some patients may benefit from treatments that help the bone marrow recover its function.
• The lower the radiation dose, the more likely it is that the person will recover from ARS.
• The cause of death in most cases is the destruction of the person’s bone marrow, which results in infections and internal bleeding.
• For survivors of ARS, the recovery process may last from several weeks up to 2 years.
• Cutaneous Radiation Injury (CRI) happens when exposure to a large dose of radiation causes injury to the skin. A doctor will suspect the presence of a CRI when a skin burn develops in a person who was not exposed to a source of heat, electrical current, or chemicals.

People with ARS typically also have some skin damage. This damage can start to show within a few hours after exposure and can include swelling, itching, and redness of the skin (like a bad sunburn). There also can be hair loss. As with the other symptoms, the skin may heal for a short time, followed by the return of swelling, itching, and redness days or weeks later. Complete healing of the skin may take from several weeks up to a few years depending on the radiation dose the person’s skin received.

What You Need to Know

• In a radiation emergency, some people may be told to take potassium iodide (KI) to protect their thyroid.
• Do not take KI unless instructed by public health or emergency response officials or a healthcare provider.
• There are limits to who should use KI and how much it can help. It only protects the thyroid from radioactive iodine (I-131) and does not protect other parts of the body from other types of radiation.
• KI is recommended only for people under 40 and pregnant or breastfeeding people. Doses recommended by the U.S. FDA depend on age.
• KI can have harmful health effects, especially if not needed or not taken correctly. If you are instructed to take KI, only use KI products that are approved by the U.S. FDA.

Potassium iodide (KI) is a type of iodine that is not radioactive and can be used to help block one type of radioactive material, radioactive iodine (I-131), from being absorbed by the thyroid.

In some radiation emergencies, usually nuclear power plant accidents, radioactive iodine may be released into the environment and enter the body through breathing or eating it. This is known as internal contamination. When the thyroid absorbs high levels of radioactive iodine, it can increase the risk of thyroid cancer in infants, children, and young adults many years after exposure. The thyroid is a gland in the neck that plays an important role in many body functions.

How KI Protects the Thyroid

KI and radioactive iodine are both types of iodine. They are both absorbed by the thyroid. For KI to work, a person must take it before or shortly after exposure to radioactive iodine. When a person takes the right amount of KI at the right time, it can help block the thyroid from absorbing radioactive iodine. This happens because the thyroid has already absorbed the KI, and there is no room to absorb the radioactive iodine. Think of filling a jar with blue marbles. If you then pour green marbles over the jar, there will not be room and they will just spill out.

Use KI Only if Instructed

Do not take KI unless you are instructed by public health or emergency response officials or a healthcare provider.  KI can cause harmful health effects. KI is helpful only in specific situations for certain groups of people.

KI should be used only as directed.

• Do not use table salt or foods as a substitute for KI. They do not help with radiation poisoning and eating large amounts could be harmful.
• Only use KI products that have been approved by the Food and Drug Administration (FDA). Dietary supplements that contain iodine may not work to protect the thyroid and can hurt you.

Limits of KI Use

KI may not give a person 100% protection. KI is most effective if taken shortly before or right after internal contamination with radioactive iodine. The effectiveness of KI also depends on how much radioactive iodine gets into the body and how quickly it is absorbed in the body.

KI is only recommended for people under 40 and pregnant or breastfeeding people. People with certain medical conditions, including known iodine sensitivity, should not take KI or should talk to a healthcare provider about whether they can safely take KI.

KI only offers limited protection for specific situations and populations:

• KI protects only against radioactive iodine and does not protect against other types of radiation.
• KI protects only the thyroid. KI does not protect other parts of the body.
• KI must be taken within 24 hours before or 4 hours after exposure to be most effective.
• KI is not a treatment and cannot reverse damage already done to the thyroid.
• KI may not give a person 100% protection from radioactive iodine.

Most radiation emergencies will involve other types of radiation and not radioactive iodine alone. Radioactive iodine is most common in nuclear power plant incidents. The best protection in a radiation emergency is always to get inside, stay inside, and stay tuned for more information from officials.

How to Take KI

KI is recommended as a medical countermeasure to protect the thyroid from radioactive iodine in people under 40 and pregnant or breastfeeding. This is because cells are still growing and multiplying more quickly in younger populations, so they can be at risk for developing thyroid cancer after breathing in radioactive iodine.

Adults over 40 years old have a much lower risk of developing thyroid cancer and are more likely to have health conditions, like problems with their thyroids, that increase their risks for harmful health effects from KI. However, officials or healthcare providers may instruct adults over 40 to consume KI if the predicted exposure is high enough to cause hypothyroidism.

Breastfeeding people should consider temporarily stopping breastfeeding until evacuated from the impacted area, if possible, and safely feed your baby other ways. Radioactive iodine can be passed to infants through breast milk.

There are two U.S. FDA-approved forms of KI:

• Tablets in two strengths, 130 milligram (mg) and 65 mg (The tablets may be cut into smaller pieces for lower doses.)
• Oral liquid solution available in one concentration, each milliliter (mL) containing 65 mg of KI. The solution comes in a 1 oz (30 mL) bottle with a dropper marked for 1, 0.5, and 0.25 mL dosing. For reference, 5 mL of liquid is one teaspoon. One mL would be about the size of a large drop of water.

Recommended Single Dosage by Age*:

*Source: https://www.fda.gov/drugs/bioterrorism-and-drug-preparedness/frequently-asked-questions-potassium-iodide-ki

** The U.S.FDA provides instructions on how to make oral potassium iodide solution at home using KI tablets.

***Adults over 40 should only take KI when recommended by officials when predicted exposure levels are high enough to possibly cause hypothyroidism.

One dose of KI offers protection for 24 hours. Officials will tell you if another dose is needed after 24 hours.

Infants (under 1 month) have the highest risk of developing thyroid cancer from contamination with radioactive iodine. More than a single dose may lead to later problems with normal development. Other protective measures should be used. In cases where more than one dose is necessary, medical follow up may be necessary.

Harmful Health Effects

KI can have harmful health effects and can cause allergic reactions. The risk of harm from KI increases when it is not taken exactly as directed by a medical or public health official.

Harmful health effects may include:

• Gastro-intestinal (stomach) upset, rashes, and inflammation of the salivary glands.
• Allergic reaction.
• The development of hypothyroidism in infants less than one month old who receive more than one dose of KI. Hypothyroidism is a condition when the thyroid doesn’t produce enough hormones.
• Severe illness or death in people who take more KI than recommended.

What is Prussian blue?

Prussian blue is a pill that can help remove radioactive cesium and thallium from people’s bodies.

How does Prussian blue work?

Prussian blue traps radioactive cesium and thallium in the intestines and keeps them from being re-absorbed by the body.

The radioactive materials then move through the intestines and are passed (excreted) in bowel movements.

Because Prussian blue reduces the time that radioactive cesium and thallium stay in the body, it helps limit the amount of time the body is exposed to radiation.

Prussian blue reduces the biological half-life of cesium from about 110 days to about 30 days.

• Prussian blue reduces the biological half-life of thallium from about 8 days to about 3 days.

Who can take Prussian blue?

The drug is safe for most adults, including pregnant women, and children (2-12 years). Dosing for infants (ages newborn-2 years) has not been determined yet.

People who have had constipation, blockages in the intestines, or certain stomach problems should be sure to tell their doctors before taking Prussian blue.

Before taking Prussian blue, people also should be sure to tell their doctors about any other medicine they are taking.

How is Prussian blue given?

Prussian blue is given in 500-milligram capsules that can be swallowed whole.

People who cannot swallow pills can take Prussian blue by breaking the capsules and mixing the contents in food or liquid. Breaking open the capsules will cause people’s mouths and teeth to be blue during the time of treatment.

What are the side effects of Prussian blue?

The most common side effects of Prussian blue are upset stomach and constipation. These side effects can easily be treated with other medications.

People may have blue feces (stool) during the time that they are taking Prussian blue.

Where can I get Prussian blue?

Prussian blue is available only by prescription.

People SHOULD NOT take Prussian blue artist’s dye in an attempt to treat themselves. This type of Prussian blue is not designed to treat radioactive contamination and can be harmful.

What is Neupogen^® (Filgrastim)?

Neupogen^® (filgrastim) is a drug that has been used successfully for cancer patients to stimulate the growth of the white blood cells, making patients less vulnerable to infections, it is expected to help patients who have bone marrow damage from very high doses of radiation in much the same way.

A person who has received a very high dose of radiation may experience bone marrow destruction, possibly resulting in infection and uncontrolled bleeding.

Since March 2015, Neupogen^® was also approved by the U.S. Food and Drug Administration (FDA) to treat those people who have received high doses of radiation.

How does Neupogen^® work?

Patients who receive very high doses of radiation will not be able to produce new white blood cells. This will lead to a drop in the number of white blood cells in circulation.

• The patients’ own bone marrow will eventually create new blood cells, but this is a slow process.
• Until the white blood cell counts rise sufficiently, these patients are at a high risk of death from infection.

Neupogen^® can speed up the process of white blood cell creation, reducing the time that the patient is vulnerable to infection.

Who can take Neupogen^®?

People may be prescribed Neupogen^® following a high dose of radiation from a radiation emergency.

Neupogen^® is safe for most adults, but should not be taken by people who have known hypersensitivity to E. coli-derived proteins, filgrastim, or any component of filgrastim.

Children and pregnant women should take Neupogen^® with caution.

It is not known if Neupogen^® is excreted in human milk; so breastfeeding women should discuss this matter with a doctor.

How is Neupogen^® given?

Neupogen^® is given by injection under the skin.

For doctors, the treatment plan is to give Neupogen^® daily for up to 2 weeks, by subcutaneous injection.

What are the side effects of Neupogen^®?

The most common side effect of Neupogen^® is mild to moderate bone pain.

Other possible side effects of Neupogen^® include fever, diarrhea, skin rash and weakness.

Enlargement and rupture of the spleen can rarely occur in patients who are receiving Neupogen^®. Patients who develop abdominal pain, particularly in the left side, while receiving the drug should be evaluated by a doctor.

Where can I get Neupogen^®?

During a radiation emergency, doctors will provide Neupogen^® treatment as needed.

Neupogen^® can only be administered by a doctor.

What is DTPA (Diethylenetriamine pentaacetate)?

DTPA (Diethylenetriamine pentaacetate) is a medicine that can bind to radioactive plutonium, americium, and curium to decrease the amount of time it takes to get radioactive plutonium, americium, and curium out of the body.

DTPA cannot bind all of the radioactive plutonium, americium, and curium that might get into a person’s body after a radiation emergency.

DTPA cannot prevent radioactive plutonium, americium, and curium from entering the body.

How does DTPA work?

DTPA comes in two forms: calcium (Ca-DTPA) and zinc (Zn-DTPA). Both forms work by tightly binding to radioactive plutonium, americium, and curium. These radioactive materials (bound to DTPA) are then passed from the body in the urine.

DTPA works best when given shortly after radioactive plutonium, americium, and curium have entered the body. The more quickly radioactive material is removed from the body, the fewer and less serious the health effects will be.

When given within the first day after internal contamination has occurred, Ca-DTPA is more effective than Zn-DTPA. After 24 hours have passed, Ca-DTPA and Zn-DTPA are equally effective.

After 24 hours, DTPA binds less effectively to radioactive plutonium, americium, and curium. However, DTPA can still work to remove these radioactive materials from the body several days or even weeks after a person has been internally contaminated.

Who can take DTPA?

Doctors and public health authorities will work together to decide who likely will benefit from DTPA treatment.

For doctors who may be administering DTPA for patients, use the following guidelines:

• Infants (including breastfed infants) and children less than 12 years of age can be given either Ca-DTPA or Zn-DTPA.
  • The dosage of DTPA should be based on the child’s size and weight.
  • The safety and effectiveness of the inhaled route of DTPA has not been studied in children.
• Young adults and adults internally contaminated with plutonium, americium, or curium should receive Ca-DTPA if treated within the first 24 hours after contamination. After 24 hours, if additional treatment is needed, adults should receive Zn-DTPA. If Zn-DTPA is not available, patients may receive Ca-DTPA together with a vitamin and mineral supplement that contains zinc.
• Pregnant women should be treated with Zn-DTPA, unless the woman has very high levels of internal contamination with plutonium, americium, or curium.
  • Ca-DTPA should be used in pregnant women only to treat very high levels of internal radioactive contamination.
  • In this case, doctors and public health authorities may prescribe a single dose of Ca-DTPA, together with a vitamin and mineral supplement that contains zinc, as the first treatment.
  • After the first dose of Ca-DTPA, treatment should continue 24 hours later with a daily dose of Zn-DTPA, as needed.
• Breastfeeding women who are internally contaminated with plutonium, americium, or curium can be treated with Ca-DTPA or Zn-DTPA.

How is DTPA given?

DTPA can be injected directly into a vein in the arm or dripped into a vein from a bag (intravenously [IV]).

Adults who have inhaled plutonium, americium, or curium can be treated with DTPA mist that is breathed into the lungs.

• Inhaling DTPA might cause some people, especially those with asthma, to cough or wheeze.
• The safety and effectiveness of inhaled DTPA has not been shown in children.

DTPA should be taken only as long as needed, as determined by a doctor.

Doctors might collect samples of blood, urine, and feces during DTPA treatment. These samples can tell the doctors how much radioactivity you are passing and how much remains in your body.

The length of treatment with DTPA will depend on:

• The amount of radioactive material in your body
• How well your body gets rid of the radioactive material with the help of DTPA.

What are the side effects of DTPA?

People who are given repeat doses of Ca-DTPA within a short period of time may have nausea, vomiting, diarrhea, chills, fever, itching, and muscle cramps.

Other side effects may include headache, light-headedness, chest pain, and a metallic taste in the mouth.

Ca-DTPA should be used cautiously in patients with a blood disease called hemochromatosis.

Ca-DTPA (and Zn-DTPA) bind to important minerals that the body needs (zinc, magnesium, and manganese). As a precaution, patients receiving long-term treatment with DTPA should be given a vitamin and mineral supplement that contains zinc.

Where can I get DTPA?

During a radiation emergency, doctors will provide DTPA treatment as needed.

DTPA can only be administered by a doctor.