FDA Issues Emergency Use Authorization for Generic Over-the-Counter Drug to Treat New World Screwworm in Dogs and Cats
Most dogs and cats in the U.S. are at low risk of NWS; risk is elevated for pets recently in areas with confirmed cases of NWS
Silver Spring, MD / CRWE PRESS RELEASE / June 09, 2026 - The U.S. Food and Drug Administration today issued an Emergency Use Authorization (EUA) for generic Nitenpyram Tablets (nitenpyram) for the treatment of New World screwworm (NWS) infestations (myiasis) in dogs, puppies, cats, and kittens that weigh at least two pounds and are at least four weeks old. This is the first generic animal drug authorized for use against NWS.
“The U.S. government is maintaining an aggressive approach to stop the spread and eradicate this pest,” said U.S. Health and Human Services Secretary Robert F. Kennedy Jr. “When I signed the initial emergency declaration back in August 2025, we established a proactive defense. Today’s authorization is the latest tactical tool in that ongoing containment strategy — providing an affordable, fast-acting treatment for dogs and cats in affected areas.”
The FDA has concluded that based on the totality of the scientific evidence available, it is reasonable to believe that Nitenpyram Tablets may be effective in the treatment of NWS myiasis in certain dogs, puppies, cats, and kittens, and the known and potential benefits of the product outweigh its 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.”
“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.”
“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.”
NWS flies lay eggs in open wounds or mucous membranes of mammals and the larvae hatch within hours and burrow into the animal's flesh. Nitenpyram works quickly, killing most NWS larvae within hours of the first dose. Pet owners should administer a second dose six hours after the first. Because the effects are short-acting, Nitenpyram Tablets do not prevent NWS myiasis or protect against reinfestation.
Following treatment with Nitenpyram Tablets, a veterinary professional may need to physically remove any remaining live or dead larvae. This task is best performed by someone with training in veterinary medicine to minimize the risk of infection or further tissue damage. Pet owners should consult a veterinarian about appropriate wound care and how to minimize the risk of reinfestation.
Nitenpyram Tablets are available over the counter and come in two tablet sizes: 11.4 and 57 mg. Dosage is based on a dog’s or cat’s weight. Do not administer to pets less than two pounds.
Detailed product information about Nitenpyram Tablets can be found in the Fact Sheet: Emergency Use Authorization of Nitenpyram Tablets (nitenpyram) for New World Screwworm (NWS). Refer to the package insert for safety information related to redosing, use in pregnant or nursing dogs and cats, and use together with other products.
Nitenpyram Tablets are sponsored by Felix Pharmaceuticals Pvt. Ltd. based in Ireland.
Related Information
- Freedom of Information Summary: Nitenpyram Tablets (EUA 006661)
- Letter of Authorization: Nitenpyram Tablets (EUA 006661)
- Fact Sheet: Emergency Use Authorization of Nitenpyram Tablets for New World Screwworm (NWS)
- Animal Drugs for New World Screwworm
- Emergency Use Authorization of Animal Drugs for NWS
- Screwworm.gov – Unified Government Response to Protect the United States
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The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, radiation-emitting electronic products, and for regulating tobacco products.
Source: U.S. Food and Drug Administration (FDA)
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