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Potassium Iodide (KI) Treatment for Animals Following a Nuclear Disaster

FACT SHEET for VETERINARIANS

What is the most important thing owners can do to protect their animals in a Nuclear Disaster?

  • Plan ahead. Animal owners should make plans in advance with friends, relatives, or shelters for housing their pets in a disaster. This will be helpful for a nuclear accident or any natural disaster.
  • Animal owners should be encouraged to purchase pet carriers.
  • Owners can use regular veterinary check-ups to practice evacuation plans from their homes.
  • Owners should have copies of their pet’s health records, including rabies vaccination.
  • Owners should have their pets micro-chipped for easy identification in an emergency.

What is KI treatment and what does it do?

  • Potassium iodide (KI) is a salt of iodine. It is one of several ingredients that can be added to tale salt to make it iodized.
  • KI has also been approved by the FDA as a nonprescription drug for use as a “blocking agent” to prevent the human thyroid gland from absorbing radioactive iodine.
  • December 10, 2001 the Food and Drug Administration issued Guidance: Potassium Iodide as a Thyroid Blocking Agent in Radiation Emergencies for use of KI in humans during a radiological emergency. There is no such national guidance for use of KI in animals available.
  • KI has a wide margin of safety, however like all medications, KI can be toxic if dosed incorrectly. Documented side effects include vomiting, drooling, runny eyes, rash, collapse and death. KI should not be used in animals with a known allergy to iodine. Suggested dose guidelines are listed below.
  • KI is a medication that can be given to humans and animals.
  • KI may not provide people or animals with 100% protection against all radioactive iodine.
  • The effectiveness of KI as a thyroid blocking agent is greatest if administered before the time of exposure to radioactive iodine, but some exposure saving can be obtained by administration shortly after exposure.

Should pets be given KI for radiological emergencies?

There are no guidelines for administration of KI for pets during an emergency. However, your clients may ask you to give KI to their pets if they have received it Potassium Iodide (KI) Treatment forAnimals Following a Nuclear Disaster because of a radiological exposure. Administration of KI should be determined by you with the owner. The following information is provided to assist you with that decision. This information is provided as guidance and recommendations only.

  • KI lessens the damage to the thyroid from radioactive iodine only. KI does not protect against other harmful radioactive rays released during a nuclear disaster.
  • Radiation is most harmful to young, actively growing animals.
  • KI must be given before or within 4 hours of exposure to be effective.
  • KI is an over-the-counter medication and you may want to stock it if there is demand in your area or special order it for the owner.
  • Do not give KI to your pet if it is sensitive to iodine.
  • Consider the age of the animal. Young animals have the highest risk of health problems from radioactive iodine and radioactive iodine causes long-term potential for thyroid cancer. Therefore, if the animal is elderly there is little chance the animal will get thyroid cancer in its lifetime (one estimate for humans was about 4 years) and elderly pets may have more problems with side effects from the KI.

Note: If a pet has been left on the property during an exposure and the owner is unable to retrieve it before 4 hours then KI will not be effective. If the pet is evacuated with the owner prior to exposure to radiation, there is no need for KI. It is our recommendation that KI only be considered for the pet if the owner has received it and the pet is with the owner.

Where can veterinarians find information regarding dosing and efficacy of KI?

Journal articles on the subject include:

  • Use of radioiodine urinalysis for effective thyroid blocking in the first few hours post exposure – Health Phys 1999 Jan;76(1):11-6
  • Potassium iodate and its comparison to potassium iodide as a blocker of 131I uptake by the thyroid in rats – Health Phys 1993 Nov;65(5):545-9
    • Reference the abstracts on page 3 of this document
    • KI comes in 130 mg and 65 mg bottles. Pro-KI™ 65 mg recommends the following dosages for pets (www.aaoobfoods.com/NBC.htm):
      • Large dogs: 1.0-2.0 tablets per day
      • Medium dogs: 0.5-1.0 tablets per day
      • Cats and small dogs: 0.25-0.5 tablet per day

Where can I get further information?

    • Contact your veterinarian with questions relating to KI and your pets.
    • www.nukepills.com has information about KI pills.
    • Mississippi Board of Animal Health (1-888-722-3106; www.mbah.state.ms.us)

REFERENCES ON KI DOSING AND EFFICACY

Health Phys 1999 Jan;76(1):11-6

Use of radioiodine urinalysis for effective thyroid blocking in the first few hours post exposure, Ribela MT, Marone MM, Bartolini P. Department of Application of Nuclear Techniques in Biological Sciences, IPENCNEN, Cidade Universitaria, Sao Paulo, Brazil.

A useful correlation between maximum thyroid uptake and radioiodine urine levels at different times after exposure was developed in order to determine when the intervention with an adequate blocking agent might still be effective. In an animal model (dog), six different doses were administered in the range of 100-600 kBq. The best correlation was found between the 125I uptake after 48 h (T-48) and urine radioactivity 4-6 h (U-4, U-5, U-6) after exposure. For the case of U-4, the equation Y(T-48) = 0.790 X(U-4) + 2.973 (r = 0.974 with a level of significance of p < 0.001) was obtained. An analogous study, carried out in humans (n = 20) to whom 1311 was administered, showed a similar correlation and level of significance: Y(T-24) = 1.162 X(U-4)+3.263 (r = 0.926; p < 0.001). The validity of this correlation was confirmed in four volunteers who received small doses of 125I(25-100 kBq), with good agreement between measured and extrapolated thyroid uptake and a mean difference of less than 10% (CV = 16.2%). Three different blocking agents were then tested in the same dog: potassium iodide, potassium perchlorate, and a thionamide (Tapazole). The blocking action of the first two compounds was about 90%, as opposed to only 48% for the third compound. Potassium iodide was chosen for its limited side effects and more universal utilization. The final study, carried out with four different doses, indicated that 25 mg of KI is the ideal amount to be administered to the dog. This corresponds to approximately 100 mg for a 70 kg human being (i.e., 1.4 mg kg(-1)). This dose, when administered to a volunteer 4 h after exposure, provided a thyroid blocking of 68%. web link

Health Phys 1993 Nov;65(5):545-9

Potassium iodate and its comparison to potassium iodide as a blocker of 131I uptake by the thyroid in rats, Pahuja DN, Rajan MG, Borkar AV, Samuel AM.

Radiation Medicine Centre, B. A. R. C., Parel, Bombay.

Potassium iodide is the preferred thyroid blocker for personnel handling radioiodine and is recommended as a prophylaxis for the population in the nearfield of a nuclear reactor which would be likely to be exposed to radioiodine in an accidental breach of containment. However, in hot and humid climates, this hygroscopic chemical has a poor shelf life due to hydrolytic loss of iodine vapors. On the other hand, another iodine-rich salt, potassium iodate (KIO3), is quite stable and has a much longer shelf life. The present study compares potassium iodide and KIO3 as thyroid blockers and examines the appropriate time at which they should be administered in case of radioiodine exposure. Either of the two were given in recommended dosage (100 mg stable iodine per 70 kg body weight) at -2, 0, +2, +4, +6, and +8 h after administration of tracer quantities of radioiodine (131I) to age-, weight-, and sex-matched rats. 131I uptake in thyroid was measured 24 h after its administration in the experimental animals and compared with placebo administered controls. Results suggest that KIO3 is as effective a thyroid blocking agent as potassium iodide. In comparison to controls, 24-h thyroid uptake of 131I can be substantially reduced if potassium iodide or KIO3 is given to the animals within 2-4 h after exposure to 131I. Another noteworthy observation is that KIO3 is effective even at 8 h when administered at twice the usual dosage in comparison to the single dose, which does not show appreciable thyroid blocking properties after 8 h.