FDA Approves First Drug to Prevent Screwworm in Pets

Protecting your pet from a devastating parasite just got easier, thanks to a breakthrough FDA decision.

The U.S. Food and Drug Administration authorized Capstar and generic Nitenpyram tablets in September 2026 as the first prevention treatment for New World screwworm in dogs and cats. Previously, pet owners could only treat infestations after they occurred, leaving animals vulnerable to painful infections caused by flesh-eating maggots.

"The FDA is addressing a previously unmet need and giving pet owners and veterinarians important tools to protect dogs and cats from NWS infestations," said Dr. Timothy Schell, director of the FDA's Center for Veterinary Medicine.

New World screwworm flies lay eggs in open wounds or body openings of animals. The hatched larvae burrow into living tissue, causing severe infections that can be fatal without treatment. While most U.S. pets currently face low risk, animals in affected regions or those traveling to certain areas south of the border need protection.

The tablets work for dogs, puppies, cats, and kittens weighing at least two pounds and four weeks old. They're available over the counter in two sizes, with dosing based on weight.

Pet owners should watch for warning signs like visible maggots or foul odors near wounds, eyes, ears, nose, or mouth. Immediate veterinary care is essential if infestation occurs.

The emergency authorization came after FDA scientists reviewed evidence showing the medication's benefits outweigh potential risks. The tablets were already being used to treat existing infestations, but this expansion to prevention marks a major step forward in animal care.

The Ripple Effect

This approval ripples beyond individual pets. Veterinarians now have better tools to protect animals in outbreak zones, reducing the spread of screwworm populations. Communities near affected areas can travel with their pets more safely, maintaining the human-animal bonds that bring so much joy to families.

The medications will remain available until health officials determine the emergency has passed. Until then, pet owners have peace of mind knowing prevention is finally possible.

Your furry family members just got a powerful new shield against a serious threat.