The revised emergency authorisations extend both prevention and treatment access to common companion-animal tablets.

The U.S. Food and Drug Administration has opened a preventive as well as treatment pathway for New World screwworm (myiasis) in dogs and cats, expanding the emergency toolkit available to veterinarians and pet owners in affected-risk areas. The move is significant for companion-animal care because it shifts one part of the response from reacting to infestations toward preventing them.

On 3 September, FDA issued an Emergency Use Authorization for Capstar, or nitenpyram tablets, and revised the authorisation for generic Nitenpyram Tablets. Both products are now authorised for prevention and treatment of New World screwworm infestations in dogs, puppies, cats and kittens that weigh at least two pounds and are at least four weeks old. The generic tablets had been authorised in June 2026 for treatment only.

FDA said that, before this action, none of the products it had authorised or conditionally approved for New World screwworm covered prevention. The agency framed the decision as a response to an unmet need for veterinarians and owners. That distinction is important for the veterinary market: a preventive indication can change the timing of clinical conversations, inventory planning and owner decisions when an animal lives in, travels to or returns from an area identified by animal-health officials as higher risk.

The emergency authorisation does not mean every dog or cat faces the same exposure. FDA continues to describe the risk as geographically uneven, and professional assessment remains central when infestation is suspected. It also does not displace wound management, surveillance or the wider public response to the parasite. The authorised use is one element of a broader framework intended to reduce the impact of myiasis in animals.

For practices, the development creates a clearer product conversation at a time when New World screwworm prevention has become part of routine preparedness in selected areas. For manufacturers and distributors, the inclusion of a branded product and its generic counterpart may support practical access. The commercial effect will still depend on supply, local risk, veterinary guidance and informed use within the emergency conditions.

For more information: U.S. Food and Drug Administration