FDA worried about Dewormer resistance

The US Food and Drug Administration (FDA) calls on animal dewormer manufacturers to voluntarily modify their product labels.

According to a press release issued by the FDA, the request was issued in an attempt to preserve the effectiveness of drugs designed to treat some internal parasites in livestock and horses. The agency would like the labels to include more information on antiparasitic resistance.

The label changes required relate exclusively to approved pesticide pharmaceutical products and do not apply to antimicrobial drugs or antimicrobial resistance. Unlike the antimicrobial issue, concern for antiparasitic drugs has no direct impact on human health. But the agency notes that antiparasitic resistance in a growing threat to animal health in the United States.

The class of drugs covered by the labeling request is anthelmintic for livestock (cattle, sheep, goats, poultry and pigs) and for horses. Anthelmintics treat internal parasites (helminths) including tapeworms and nematodes. These internal parasites are becoming increasingly resistant to drugs that were highly effective in killing them in the past. As resistance develops, the surviving worms transmit genes resistant to their offspring, creating a larger population of resistant parasites.

The FDA request specifies that the new product labels should include the following information:

  • Any use of a dewormer can result in the development of antiparasitic resistance.
  • Proper dosage is essential for the safe and effective use of a dewormer.
  • End users should work with their veterinarian to monitor herds and flocks to determine the extent of anti-parasitic resistance in a particular farm.
  • The Dewormers should be used as one part of an internal parasite control program.

The FDA calls for veterinary pharmaceutical companies to add the new language to their existing pesticide product labels by the end of 2019 and to labels for any new cattle or horse dewormer the FDA approves in the future.