Press Announcements > FDA: Pfizer will voluntarily suspend sale of animal drug 3-Nitro

For Immediate Release: June 8, 2011
Media Inquiries: Stephanie Yao, 301-796-0394, stephanie.yao@fda.hhs.govConsumer Inquiries: 888-INFO-FDA


FDA: Pfizer will voluntarily suspend sale of animal drug 3-Nitro
Company takes action in response to FDA data

The U.S. Food and Drug Administration today announced that Alpharma, a subsidiary of Pfizer Inc., will voluntarily suspend U.S. sales of the animal drug 3-Nitro (Roxarsone), a product used by poultry producers since the 1940s.

The move follows a recent FDA study of 100 broiler chickens that detected inorganic arsenic, a known carcinogen, at higher levels in the livers of chickens treated with 3-Nitro compared with untreated chickens. FDA officials stress that the levels of inorganic arsenic detected were very low and that continuing to eat chicken as 3-Nitro is suspended from the market does not pose a health risk.

“FDA detected increased levels of inorganic arsenic in the livers of chickens treated with 3-Nitro, raising concerns of a very low but completely avoidable exposure to a carcinogen,” said Michael R. Taylor, FDA deputy commissioner for foods. “We are pleased to announce that the company is cooperating with us to protect the public health.”

Arsenic is in the environment as a naturally occurring substance or as a contaminant and is found in water, air, soil, and food. Published scientific reports have indicated that organic arsenic, a less toxic form of arsenic and the form present in 3-Nitro could transform into inorganic arsenic. In response, scientists from the FDA’s Center for Veterinary Medicine and the Center for Food Safety and Applied Nutrition developed an analytical method capable of detecting very low levels of inorganic arsenic in edible tissue.

Using the new method, FDA scientists recently found that the levels of inorganic arsenic in the livers of chickens treated with 3-Nitro were increased relative to levels in the livers of the untreated control chickens.

Alpharma decided to voluntarily suspend sale of 3-Nitro and to facilitate an orderly process for suspending use of the product in the United States. Alpharma’s plan provides for continued sales of 3-Nitro for 30 days from today. The company stated that allowing sales for this period will provide time for animal producers to transition to other treatment strategies and will help ensure that animal health and welfare needs are met.

In addition, the company is working with the FDA to examine all relevant scientific data regarding the use of 3-Nitro in animals.

In 1944, 3-Nitro became the first arsenic-containing new animal drug product approved by the FDA. It is used primarily in broiler chickens. Combined with other animal drugs, 3-Nitro has been used by some in the poultry industry to help control coccidiosis, a parasitic disease that affects the intestinal tracts of animals. It has also been used for weight gain, feed efficiency and improved pigmentation.

FDA has consulted with the U.S. Department of Agriculture and is working with Alpharma to minimize the impact on the animal agriculture industry as 3-Nitro is suspended from the market.

For more information:
• FDA Study on 3-Nitro (Roxarsone) and Chicken1 ► Product Safety Information > 3-Nitro (Roxarsone) and Chicken

• Questions and Answers Regarding 3-Nitro (Roxarsone)2 ► Product Safety Information > Questions and Answers Regarding 3-Nitro (Roxarsone)


The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.

Press Announcements > FDA: Pfizer will voluntarily suspend sale of animal drug 3-Nitro