As a result, said the FDA, there are now no arsenic based drugs allowed for use in farmed animals in the US.
Zoetis Animal Health sent a letter of commitment to the FDA in April indicating it would suspend sale of Histostat 50 (nitarsone) and it formally requested the FDA withdraw backing for the drug by the end of this year.
The drug was previously approved for use to treat blackhead disease in turkeys and chickens, agency officials said. It was the only arsenic-based drug that had approval to be used in food animals.
Other similar drugs had already been removed from market, added the US agency. Published scientific reports had recently shown that organic arsenic, the less toxic form present in arsenic based animal drugs, could convert into inorganic arsenic, a known carcinogen.
The FDA approval withdrawal applies to several combination products beyond Histostat 50, including Histostat 50/BMD (bacitracin methylene disalicylate) and Histostat 50/ALBAC (bacitracin zinc).