What is potassium iodide?

Potassium iodide is a salt, similar to table salt. Its chemical symbol is KI.  It is routinely added to table salt to make it "iodized." Potassium iodide, if taken in time and at the appropriate dosage, blocks the thyroid gland's uptake of radioactive iodine and thus could reduce the risk of thyroid cancers and other diseases that might otherwise be caused by exposure to radioactive iodine that could be dispersed in a severe nuclear accident.

 

What is the role of potassium iodide in radiological emergency preparedness?

The purpose of radiological emergency preparedness is to protect people from the effects of radiation exposure after an accident at a nuclear power plant.  Evacuation is the most effective protective measure in the event of a radiological emergency because it protects the whole body (including the thyroid gland and other organs) from all radionuclides and all exposure pathways. However, in situations when evacuation is not feasible and in-place sheltering is substituted as an effective protective action, administering potassium iodide is a reasonable, prudent, and inexpensive supplement to evacuation and sheltering.

Potassium iodide is a special kind of protective measure in that it offers very specialized protection. Potassium iodide protects the thyroid gland against internal uptake of radioiodines that may be released in the unlikely event of a nuclear reactor accident.

 

What is the benefit of taking potassium iodide during a radiological accident?

When potassium iodide is ingested, it is taken up by the thyroid gland. In the proper dosage, and taken at the appropriate time, it will effectively saturate the thyroid gland in such a way that inhaled or ingested radioactive iodines will not be accumulated in the thyroid gland.  The risk of thyroid effects is reduced.  Such thyroid effects resulting from radioiodine uptakes  due to inhalation or ingestion, or both, could result in acute, chronic, and delayed effects. Acute effects from high doses include thyroiditis, while chronic and delayed effects include hypothyroidism, thyroid nodules, and thyroid cancer.

 

PREPARATION FOR 130 MG POTASSIUM IODIDE TABLET

1. Grinding the potassium iodide tablet into powder

  • Put one 130mg potassium iodide tablet into a small bowl and grind it into a fine powder using the back of the metal teaspoon against the inside of the bowl. The powder should not have any large pieces.

2. Mixing potassium iodide powder into a drink

  • Add four teaspoonfuls of water to the potassium iodide powder in the small bowl. Use a spoon to mix them together until the potassium iodide powder is dissolved in the water.

3. Mix drink of choice with potassium iodide powder and water solution

  • Add four teaspoonfuls of drink to the potassium iodide powder and water mixture described in Step 2.

The amount of potassium iodide in the drink is 16.25 mg per teaspoon. The number of teaspoonfuls of the drink to give your child depends on your child's age. There is a chart at the end of these directions to tell you how much to give your child.

The potassium iodide in any of the six drinks listed above and infant formulas will keep for up to seven days in the refrigerator. FDA recommends that the potassium iodide drink mixtures be prepared weekly; unused portions should be discarded.

ADMINISTRATION

FDA recommends doses for potassium iodide based on age, predicted thyroid exposure to radioiodines, and -for women -- whether the woman is pregnant or nursing (see Table 1). Adults over 18 years of age and pregnant or lactating women should take the potassium iodide 130-mg tablet. Infants, children, and adolescents through 18 years of age should take potassium iodide in a drink prepared according to the procedure described above. Table 2 shows how many teaspoonfuls of potassium iodide mixture to give to an adolescent, child, or infant. The dose of potassium iodid e should be taken once a day until a risk of significant exposure to radioiodines no longer exists.

Table 1. Threshold thyroid radioactivity exposures and the recommended dose of Potassium iodide (KI) for different groups 1 .

If you are:

And your predicted Thyroid Exposure is

Then you should take:

Number of

130 mg tablets

An adult over the age of 40

Equal to or greater than 500 centi-grays (cGy)

a 130 mg dose of potassium Iodide (KI)

1

An adult between the ages of

18 and 40

Equal to or greater than 10 cGy

A pregnant or lactating woman

Equal to or greater than 5cGy

 

Table 2. Recommended doses of KI for adolescents, children, and infants with predicted thyroid radioactivity exposures equal to or greater than 5 cGy 1 , using 130 mg tablet preparations.

If your child is:

Give your child this amount of Potassium Iodide (KI) *

Which is

An adolescent between 12 and 18 years old**

4 teaspoonfuls

(NOT tablespoonfuls)

65 mg of potassium iodide (KI)

Between 4 and 12 years old

4 teaspoonfuls

(NOT tablespoonfuls)

65 mg of potassium iodide (KI)

Over 1 month through 3 years

2 teaspoonfuls

(NOT tablespoonfuls)

32.5 mg of potassium iodide (KI)

An infant from birth through 1 month

1 teaspoonful

(NOT a tablespoonful)

16.25 mg of potassium iodide (KI)

* This is the amount to give your child for one dose. You should give your child one dose each day.

** Adolescents approaching adult size [equal to or greater than 154 pounds (70 kg)] should receive the full adult dose (130 mg tablet or 8 teaspoonfuls of KI mixture).

 

PREPARATION FOR 65 MG POTASSIUM IODIDE TABLET

If you have potassium iodide 65 mg tablets, then prepare the mixture as described below:

1. Grinding the potassium iodide 65 mg Tablet into Powder

  • Put one 65mg potassium iodide tablet into a small bowl and grind it into a fine powder using the back of the metal teaspoon against the inside of the bowl. The powder should not have any large pieces.

2. Mixing potassium iodide Powder into a Drink

  • Add four teaspoonfuls of water to the potassium iodide powder in the small bowl. Use a spoon to mix them together until the potassium iodide powder is dissolved in the water.

3. Mix drink of choice with potassium iodide powder and water solution

  • Add four teaspoonfuls of drink to the potassium iodide powder and water mixture described in Step 2.

The amount of potassium iodide in the drink is 8.125 mg per teaspoon. The number of teaspoonfuls of the drink to give your child depends on your child's age. Table 3 shows how many teaspoonfuls of potassium iodide mixture to give to an adolescent, child, or infant.

Please pay attention to the number of teaspoonfuls recommended when using a potassium iodide 65 mg tablet as it is different from the number of teaspoonfuls given when using a potassium iodide 130 mg tablet.

Table 3. Recommended doses of KI for children and infants with predicted thyroid radioactivity exposures equal to or greater than 5 cGy 1 , using 65 mg tablet preparations.

If your child is:

Give your child this amount of potassium iodide (KI) *

Which is

Between 4 and 12 years old

8 teaspoonfuls

(NOT tablespoonfuls)

65 mg of potassium iodide (KI)

Over 1 month through 3 years

4 teaspoonfuls

(NOT tablespoonfuls)

32.5 mg of potassium iodide (KI)

An infant from birth through 1 month

2 teaspoonfuls

(NOT tablespoonfuls)

16.25 mg of potassium iodide (KI)

* This is the amount to give your child for one dose. You should give your child one dose each day.