http://www.nytimes.com/2001/11/29/national/29RADI.html

November 29, 2001

RADIATION THREAT

Agency Weighs Buying Drug to Protect Against Radiation-Induced Ailments

By MATTHEW L. WALD

ASHINGTON, Nov. 28 — Spurred by the attacks in September, the Nuclear Regulatory Commission is moving toward buying millions of doses of a drug that protects against thyroid cancer that might result from radiation exposure.

The idea of stockpiling the drug, potassium iodide, has been debated since the 1979 accident at Three Mile Island, near Harrisburg, Pa. Proponents renewed discussions of the proposal after the explosion of the Chernobyl reactor in the Ukraine, a 1986 accident that is now blamed for thousands of thyroid cancers, mostly in people who were in utero or younger than 2 years old at the time. Those people, regardless of their age, who took potassium iodide at the time were protected.

In 1998, the commission decided to offer the drug free to any state that wanted to stockpile it, but the following year it reversed itself and rescinded the offer.

Now the commission has set aside $800,000, enough to buy millions of doses to offer to states, and is waiting for a guidance document from the Food and Drug Administration on how big a radiation dose warrants use of the drug, and how much of the drug should be given to babies, children, adults and pregnant women.

The guidance, based on data from Chernobyl, will call for using potassium iodide at far lower levels of exposure to radiation than previously recommended, said Dr. David G. Orloff, who is in charge of the document. It will conclude that the benefits of use far exceed risks, even though some people may have adverse reactions, Dr. Orloff said.

The earlier recommendation was based on data from the Hiroshima atomic bomb blast in 1945.

William Beecher, the commission's chief spokesman, said that the agency was eager to proceed. The F.D.A. document, he said, is "the missing piece," and when it is completed, his agency will enter negotiations with pharmaceutical companies for a large order, and then ship pills to any state that wants to stockpile them near a nuclear plant.

But the new recommendation is far more complex, establishing different recommended doses and different conditions for use for eight categories of people: newborns; infants younger than 3 years old; children 3 to 12; youths 12 to 18; adults 18 to 40; adults older than 40; and women who are lactating or are pregnant.

For those younger than 18 and for pregnant or lactating women, the F.D.A. will recommend giving the drug at a level of radiation exposure a fifth as large as advised in the 1980's.

Dr. Orloff, director of the division of metabolic and endocrine drug products at the Food and Drug Administration, said, "What's happened between 1982 and now is Chernobyl, and the rash of thyroid cancers that occurred in the aftermath, notably in children who were between zero and 4 years old at the time of the accident."

The World Health Organization has called for giving children potassium iodide at an anticipated radiation dose one-fifth of the standard to be proposed by the F.D.A.

But Dr. Orloff said the disparity is not serious. The larger problem, he said, is predicting the radiation dose from an unfolding accident.

"The ability to predict in advance, when you see smoke starting to billow, what the precise exposure is going to be, is pretty poor," he said.

When reactors split uranium atoms, one of the fragments is an intensely radioactive form of iodine, which can be absorbed by people directly or can land in pastures, where it is eaten by cows and concentrated in their milk. One reason children are vulnerable is that they drink more milk than adults do.

Potassium iodide works by saturating the human thyroid gland with normal iodine so it cannot absorb radioactive iodine. Potassium iodide can cross the placenta, but the prime protective mechanism in pregnant women is that its use reduces the ability of the mother to absorb the radioactive variety.

But the drug must be given before the radiation exposure, or very soon after, which means it must be stored near the site of potential exposure.

Adverse reactions are rare, but are more common among people older than 40, said the F.D.A., which set a radiation exposure threshold for those people at 100 times the level for children and adolescents.

ALL INFORMATION, DATA, AND MATERIAL CONTAINED, PRESENTED, OR PROVIDED HERE IS FOR GENERAL INFORMATION PURPOSES ONLY AND IS NOT TO BE CONSTRUED AS REFLECTING THE KNOWLEDGE OR OPINIONS OF THE PUBLISHER, AND IS NOT TO BE CONSTRUED OR INTENDED AS PROVIDING MEDICAL OR LEGAL ADVICE.  THE DECISION WHETHER OR NOT TO VACCINATE IS AN IMPORTANT AND COMPLEX ISSUE AND SHOULD BE MADE BY YOU, AND YOU ALONE, IN CONSULTATION WITH YOUR HEALTH CARE PROVIDER.