An arsenic-based drug used to prevent a parasitic disease in poultry will become unavailable this fall.
The removal follows published scientific reports indicating organic arsenic present in such drugs can transform into inorganic arsenic, a carcinogen.
A Food and Drug Administration announcement published in April indicates Zoetis Animal Health will suspend sales of its nitarsone product Histostat this fall and request FDA withdrawal of the drug approval. Nitarsone is the only drug available to prevent blackhead disease, or histomoniasis, in chickens and turkeys.
The agency has withdrawn approvals for other arsenic-based animal drugs: roxarsone, arsanillic acid, and carbasone, FDA information states. Alpharma had suspended marking of its roxarsone product 3-Nitro, which was used to treat coccidiosis and improve production, in 2011 after an FDA study found increased inorganic arsenic in livers of chickens fed roxarsone.
In 2013, the FDA denied a petition to revoke approvals of the four arsenic-based drugs. Two advocacy organizations, the Center for Food Safety and the Institute for Agriculture and Trade Policy, had filed the petitions.
The FDA determined the request was moot with respect to three drugs, and the agency was working on studies and evaluations related to safety of arsenic-based animal drugs and had not concluded whether to initiate proceedings to withdraw approval of nitarsone.