Why Are Potassium Iodide Pills Selling Like Crazy?

Potassium iodide is a chemical compound sold as a medicine or supplement and sometimes used to treat overactive thyroid conditions, such as hyperthyroidism. Iodine is also found in foods like fish, dairy products and iodized salt, and plays an important role in maintaining metabolism.

The reason potassium iodide has become so sought after in recent weeks? The tablets are often doled out to people exposed to radiation following a nuclear disaster to protect against thyroid cancer, says Dr. Keith W. Roach, an internal medicine doctor and associate professor of Clinical Medicine at Weill Medical College of Cornell University. He's also the author of "To Your Good Health," a medical advice column syndicated in more than 150 newspapers, where he recently addressed questions about potassium iodide.

Any time there is the real or perceived threat of a nuclear attack, people start scrambling for the stuff, Troy Jones, president of sales and marketing for Anbex, Inc., makers of the potassium iodide brand iOSAT, recently told CNN. For example, there was another surge in potassium iodide sales in 2018, after former president Donald Trump tweeted that he had a "much bigger & more powerful" button than North Korea's Kim Jong-un.

Now people want to get their hands on the tablets after Russian troops took control of Chernobyl, the site of the world's worst nuclear power plant accident. You'll remember that in 1986 Chernobyl spewed a cloud of radioactive material into the atmosphere endangering millions of people in the former USSR and present-day Ukraine. Reactor No. 4 has been sealed off and is protected, but has to be monitored 24 hours a day.

"The big run [on iOSAT] started Feb. 23 through Feb. 28. We sold out all the inventory we had," Jones told CNN. Even after supplies were replenished, sales continued to spike well into March.

During a nuclear radiation emergency, such as a nuclear power plant accident, an explosion of a nuclear weapon or an attack from a so-called "dirty bomb," radioactive material can be released into the air or water. The main radioactive materials, or radionuclides that pose a risk to human health include radioactive caesium and radioactive iodine, also referred to as radioidine. Someone can become exposed to these radionuclides following a nuclear radiation emergency by breathing air or eating food contaminated with radioactive chemicals.

Radioactive iodine, in particular, will concentrate in the thyroid, the butterfly-shaped gland on the front of the neck that produces hormones that regulate the body's metabolic rate. This can harm the thyroid and cause thyroid cancer later on, Roach explains.

If taken early enough — ideally, within three to four hours of exposure — potassium iodide can protect the thyroid from radioactive iodine by blocking all the available space in the thyroid gland for the radioactive iodine to bind. "That's when potassium iodide becomes an important health issue," Roach says.

Potassium iodide is recommended by the U.S. Food and Drug Administration (FDA), the Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO) for use in the event of a nuclear disaster. In such instances, the supplement is offered to people within 10 to 20 miles (16 to 32 kilometers) of the nuclear plant.

However, there's no way of knowing how far a radioactive iodine cloud might spread. "The [radioactive] iodides go with the wind and get caught into rain clouds and rain down in vast areas so that food and water can become contaminated," Roach explains. "Even people who live a long way from the blast can be exposed."

After Chernobyl, higher than expected rates of thyroid cancer were found in people who lived more than 200 miles (321 kilometers) from the nuclear plant, according to the American Thyroid Association, which supports wider distribution of the supplements.

According to the American Thyroid Association, thyroid cancer isn't very common compared to other cancers, and is highly treatable. In general, about 90 percent of thyroid cancer patients survive. But not all thyroid cancers carry the same prognosis, Roach explains.

The most common type — papillary thyroid cancer — is very curable. "But there are some cancers that are really bad and ones due to excess radiation are not as well behaved as typical thyroid cancer," he says.

There's no doubt potassium iodide can protect against thyroid cancer if you've been exposed to radioactive iodine and been treated at the right time with the proper dosage. But even if your thyroid is protected, you are still at risk for cancer.

"There's the rub," Roach says. "A nuclear device produces many different types of radiation, only a small portion of which is mediated through the iodides, like cesium iodide, for example. So, the potassium iodide protects you from part of the radiation exposure, but it doesn't protect you from any of the others.

For example, among Japanese atomic bomb survivors, the risk of leukemia increased a few years after radiation exposure whereas the risks of other cancers increased more than 10 years after exposure, according to Columbia University's Center for Nuclear Studies. But many long-term studies have found that after the meltdown at Chernobyl, there was only a slightly higher risk of leukemia in the most contaminated regions, yet there was still a dramatic increase of childhood and adolescence thyroid cancers.

The FDA has not made specific recommendations for people to purchase or use potassium iodide. But if you live in the U.S. and within 10 miles (16 kilometers) of a nuclear reactor or an emergency planning zone, chances are you are covered. That's because thanks to an arrangement with the Nuclear Regulatory Commission, those states purchase potassium iodide to keep on hand.

If you live farther away, it could be days before the cloud of radioactive debris rains down on your food and water supply, so there is time to get your hands on potassium iodide. As a medical professional, Roach says he's not concerned, though, and he's not far from Three Mile Island, the site of the most serious nuclear power plant accident in the U.S., and he's not stockpiling potassium iodide.

"Because health officials have mass amounts of it. It's something that they would be able to get to the population fast," he says.

But, if it gives you peace of mind, then buy it. "There's an extremely small benefit from having it," Roach says. "On the other hand, the stuff costs a couple dollars a dose. So, if people say, 'Well, I want to have it,' then I say, 'then you do that.'

"If you're worried enough to put a year's supply of food in your bomb shelter, then you're the sort of person who is going to have potassium iodide," he says. "The rest of us are willing to take this infinitesimal risk."

Potassium iodide is available without a prescription, but you won't find it on the shelves of some of the nation's largest drugstores, like CVS or Walgreens. Instead it's available via online pharmacies, but do beware of fakes, such as tablets and liquid that claim to be iodide or dietary supplements that promise to protect against radiation.

Only four potassium iodide products are approved by the FDA to be marketed in the U.S.:

A single 130 mg dose of potassium iodide, or a 56 mg dose for children ages 3 to 12, protects the thyroid for approximately 24 hours. It should be dosed daily until the risk of exposure no longer exists. Taking a more than recommended dosage or taking a stronger dose than recommended does not offer more protection and can cause severe illness or death, the CDC warns.

Potassium iodide is not recommended for individuals with certain health conditions. But otherwise, if taken as recommended, the medicine carries very few side effects.

If you do choose to buy potassium iodide to have on hand "just in case," Roach echoes the CDC's recommendation that it only be taken upon the advice of public health or emergency management officials.