Animal & Veterinary

Arsenic-based Animal Drugs and Poultry

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® (roxarsone), an approved animal drug, 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 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, a subsidiary of Pfizer, Inc., decided to voluntarily suspend sale of 3-Nitro® and to facilitate an orderly process for suspending use of the product in the United States. Ownership of the veterinary drug subsequently changed to Zoetis, Inc., who continued the suspension from sale of 3- Nitro®. On February 27, 2014, Zoetis, Inc. voluntarily withdrew the new animal drug application for 3- Nitro®. On the same day, Zoetis, Inc. and Huvepharma AD voluntarily withdrew all new animal drug approvals and supplements for 3- Nitro®, as well as arsanilic acid and carbarsone (two other arsenical new animal drugs) for use in animal feed (including all combinations with other approved new animal drugs).

On April 1, 2015, Zoetis announced that it would discontinue marketing Histostat (nitarsone), the only remaining arsenic-based animal drug on the market, by Fall 2015, and would request withdrawal of the approval for the drug by the end of 2015. Histostat (nitarsone) is approved for the prevention of histomoniasis (blackhead disease) in turkeys and chickens, and is the only approved animal drug for this indication. Histomoniasis is a disease that occurs regionally and seasonally in turkeys, and causes significant mortality. Histostat (nitarsone) will cease to be available in the 2016 growing season.

Page Last Updated: 04/24/2015
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