People in the United States are rushing out to take iodine pills, specifically in the form of potassium iodide, to combat the threat of radiation spreading from the nuclear events stemming from the Japan earthquake and tsunami.

There are numerous reports that pharmacies in California have run out of the drug.

Potassium iodide works when the thyroid takes it up, instead of the potentially dangerous radioactive iodine that comes from a nuclear fallout. In theory, this can protect thyroid from potential cancer due to radiation exposure.

But, according to numerous experts, the threat of radiation from the crippled Japanese nuclear reactors to the United States is extraordinarily low.

As reported in MedPage Today,

Jonathan E. Fielding, MD, MPH, health officer for Los Angeles County, said he and other public health authorities still believe that Californians faced “minimal risk of radiation exposure” from the Japanese nuclear facility, even though news reports indicated that a series of explosions had breached the containment building surrounding one reactor.

“I want to stress that there is no reason to purchase potassium iodide at this time,” he said. Fielding also urged those who had already bought the pills not to take them, as they can have adverse effects.

Iodine tablets typically work when taken before radiation exposure, or immediately after.  So, in the cases of panicked California residents, it’s unlikely that taking potassium iodide will protect them.

And there are side effects as well, including inflammation of the salivary gland, allergic reactions, and gastrointestinal side effects.

Worse, according to USA Today,

taking the pills too late — a week after exposure — can actually cause radioactive iodine to get locked in the thyroid, Inabnet says. That’s what happened at Chernobyl.

Instead of spending time and money to find and purchase iodine, it’s much more useful to use those dollars and contribute to the Japan earthquake and tsunami relief efforts instead.

Kevin Pho is an internal medicine physician and on the Board of Contributors at USA Today.  He is founder and editor of KevinMD.com, also on Facebook, Twitter, Google+, and LinkedIn.