The U.S. Food and Drug Administration has issued an Emergency Use Authorization for generic Nitenpyram Tablets to treat New World screwworm infestations, also known as myiasis, in dogs, puppies, cats and kittens that weigh at least two pounds and are at least four weeks old.

It marks the first generic animal drug authorized for use against New World screwworm, a news release from the FDA said.

“The U.S. government is moving aggressively to contain and eliminate New World screwworm,” U.S. Health and Human Services Secretary Robert F. Kennedy, Jr. said in the release. “Today’s authorization is the latest HHS action to strengthen our response. It puts an affordable, fast-acting treatment in the hands of pet owners, strengthens our containment strategy, and helps stop this destructive parasite from spreading further in the United States.”

The FDA said it determined, based on the totality of the scientific evidence available, that it is reasonable to believe Nitenpyram Tablets may be effective in treating New World screwworm myiasis in certain dogs, puppies, cats and kittens and that the known and potential benefits outweigh the known and potential risks.

“The FDA has spent nearly a year fast-tracking reviews and readying for the arrival of New World screwworm in the U.S.,” said Acting FDA Commissioner Kyle Diamantas. “As of today, under the Trump administration’s decisive leadership, the FDA has issued ten EUAs and three conditional approvals for drugs to combat this threat, and this count will continue to grow as we receive more animal drug submissions and unleash American regulatory speed.”

New World screwworm flies lay eggs in open wounds or mucous membranes of mammals, and larvae hatch within hours before burrowing into an animal’s flesh. Nitenpyram works quickly, killing most larvae within hours of the first dose. Pet owners are directed to give a second dose six hours after the first. Because the effects are short-acting, Nitenpyram Tablets do not prevent myiasis or protect against reinfestation.

Following treatment, a veterinary professional may need to physically remove any remaining live or dead larvae. Officials said the procedure is best handled by trained veterinary personnel to reduce the risk of infection or further tissue damage. Pet owners are advised to consult a veterinarian for wound care guidance and steps to reduce reinfestation risk.

“Generic animal drugs build resilience in our domestic supply chain and play a critical role in expanding the toolkit of U.S. veterinary drugs for New World screwworm,” said Timothy Schell, Ph.D., director of the FDA’s Center for Veterinary Medicine. “By authorizing this generic treatment, FDA is reinforcing our commitment to providing timely, affordable options to safeguard animal health for American pet owners.”

The tablets are available over the counter in two strengths, 11.4 mg and 57 mg, with dosage based on the animal’s weight. The drug should not be administered to pets weighing less than two pounds.

“The Trump Administration is taking a whole of government approach to fighting New World screwworm. USDA has been working with our partners to prepare for this day and were ready day one to spring into action,” said U.S. Department of Agriculture Secretary Brooke Rollins. “HHS and FDA have been great partners in this fight, and I am thankful to Secretary Kennedy for making sure cat and dog owners have access to treatment should they need it.”

Detailed product information is available in the Fact Sheet: Emergency Use Authorization of Nitenpyram Tablets (nitenpyram) for New World Screwworm (NWS). Safety details, including redosing, use in pregnant or nursing dogs and cats and use alongside other products, are included in the package insert.

Nitenpyram Tablets are sponsored by Felix Pharmaceuticals Pvt. Ltd. based in Ireland.