Once again, the evening news has me scratching my head and wondering if it is time to call my healthcare provider to secure a prescription for Potassium Iodide or even Prussian Blue? As a nurse and healthsystem analyst, I want to protect my family. But wait! I have a shellfish allergy, and one television medical expert said that I might not be able to take Potassium Iodide at all. Are the drugs safe for all my family members? What about my dog, Oscar? Time to revisit some facts.
There are several pharmacological agents that are being mentioned as being important to limit the effects of internal contamination from radioactive materials. Standard planning and response activity around a nuclear reactor includes a variety of activities, including issuing Potassium Iodide (KI) to those individuals who may have been exposed to Iodine 131 (I-131). Another drug, Prussian blue, is a “chelating” agent that can remove radioactive materials from the body by binding with them. Prussian blue is effective for treating exposure to Cesium and Thallium. Cesium-137 (Cs-137) has been detected from the smoke coming out of the Fukushima nuclear power plant in Japan. (Prussian blue is also a paint color well known to artists, but medical Prussian blue is formulated differently – so please don’t eat the paint!) A third drug, Diethylenetriamene pentaacetate (DTPA), is also a chelating agent. DTPA is approved by the Food and Drug Administration (FDA) for chelation of Plutonium, Americium and Curium. None of these radioisotopes (Plutonium, Americium or Curium) have been associated with the nuclear reactor fires in Japan.
The smoke and escaping steam from the nuclear reactor fires carries particulates (dirt/soot), as well as the isotopes mentioned above. Particles in the air can be absorbed through breathing, entering our skin from contamination of our clothes or open skin wounds, and/or swallowing particles (such as with mucus in our nose or mouth). Internal contamination from particles in the air in our home or outside occurs on a daily basis, such as with work environments, being around burning candles or where air pollution is present. The goal of post-exposure medication, such as KI or Prussian blue, is to bind with the radioisotopes which have entered the body, and to limit the effect of tissue damage caused by radiation.
Potassium Iodide (KI) is a salt. Iodine is naturally available in some foods as well as in “iodized” table salt (iodized salt is not radioactive), and is used by the body’s thyroid gland to make thyroid hormones. The thyroid gland is located in the front part (anterior portion) of the neck, behind the windpipe. Following exposure to I-131, radioactive iodine particles are absorbed by the thyroid gland. Prolonged exposure to I-131 has been associated with an increased risk of thyroid cancer, especially in children. KI works by being quickly absorbed by the thyroid gland and prevents I-131 from attaching itself to the thyroid tissue. So, it makes sense to take KI before an I-131 exposure, or as quickly as possible following one. Adults over age 40 have the lowest chance of developing thyroid cancer after contamination with radioactive iodine. According to the CDC (http://emergency.cdc.gov/radiation), adults are at greatest risk of having allergic reactions to KI. Having a shellfish or seafood allergy by itself does not mean one will have an allergic response to KI, as there are other factors to consider. A daily dose of KI will protect the thyroid for 24 hours. Individuals who have pre-existing thyroid conditions should have medical supervision when taking KI to monitor for side effects. The drug has been reported safe in prescribed doses for most adults, children and nursing mothers. KI is not a prescription drug, and is available over the counter. Check with the pharmacist or your healthcare provider for dosing instructions. Most importantly, if there is no threat to you or your family from exposure to I-131, there is no need to take KI.
Our pet dogs can also be given KI for an exposure to I-131, but in much lower doses. Check with your veterinarian for the correct dose and an animal specific prescription. http://www.ncbi.nlm.nih.gov/pubmed/9883942?dopt=Abstract.
Prussian blue works in a similar manner and binds to Cs-137 in the digestive tract. In 1987, Prussian blue was used to treat the accidental poisoning of individuals who encountered discarded Cs-137 capsules in Goiana, Brazil. Prussian blue is removed from the digestive tract by normal bowel movements. It reduces the biological half life of Cs-137 from 70-110 days to about 30 days. The drug has been reported as safe for nursing mothers, most adults and children. The dose will vary with age and body size. The medication comes in a capsule form, and is usually taken three times per day. The amount of time an individual needs to take Prussian blue will vary with the amount of contamination one is exposed to. Prussian blue is available only by prescription.
Our pet dogs can also be given Prussian blue for an exposure to Cs-137, but in much lower doses. One study noted that the drug was more effective in younger dogs, compared with older dogs. Check with your veterinarian for the correct dose and an animal specific prescription. http://rpd.oxfordjournals.org/content/79/1-4/473.short
So, is a pill for prevention worth a pound of cure? My answer is “yes”, but with certain caveats: Make sure the exposure is for real. Check with local emergency management and public health authorities first. Follow the dosing requirements recommended by your healthcare provider or veterinarian, and take only if it is truly needed.
See IEM’s website for more information on our capabilities and experience in medical consequence modeling, health and emergency preparedness and radiological emergency preparedness.
Author: Debbie Kim APRN, MSN, Sr. Health Care System Analyst