FDA Issues Emergency Use Authorizations for Drugs to Treat New World Screwworm in Dogs and Cats
Feb 18, 2026
The U.S. Food and Drug Administration issued (Feb. 18, 2026) two Emergency Use Authorizations (EUAs) – one for NexGard (afoxolaner) chewable tablets for the treatment of New World screwworm (NWS) infestations (myiasis) in dogs, and the second for NexGard COMBO (esafoxolaner, eprinomectin, and praz
iquantel topical solution) for the treatment of NWS myiasis in cats.
For NexGard, the agency has concluded that based on the scientific evidence available, it is reasonable to believe that NexGard may be effective in the treatment of NWS myiasis in dogs and puppies, and the known and potential benefits of the product outweigh its known and potential risks.
For NexGard COMBO, the agency has concluded that based on the scientific evidence available, it is reasonable to believe that NexGard COMBO may be effective in the treatment of NWS myiasis in cats and kittens, and the known and potential benefits of the product outweigh its known and potential risks.
These EUAs will be effective until they are revoked or the HHS Secretary terminates the declaration that the potential public health emergency presented by NWS justifies the emergency use authorization of animal drugs for NWS.
As of February 18, 2026, NWS has not been detected in the United States. Most dogs and cats in America are at low risk of NWS due to their geographic location; however, pets near the U.S.-Mexico border and pets that have traveled to countries with active NWS cases are more likely to be exposed to NWS.
NexGard and NexGard COMBO are available only by prescription from a licensed veterinarian because professional expertise is required to monitor for and respond to potential adverse reactions. Detailed product information about NexGard for veterinary practitioners can be found in the Fact Sheet for Veterinarians: Emergency Use Authorization of NexGard (afoxolaner) Chewables for New World Screwworm (NWS) for dogs. Detailed product information about NexGard COMBO for veterinary practitioners can be found in the Fact Sheet for Veterinarians: Emergency Use Authorization of NexGard COMBO (esafoxolaner, eprinomectin, and praziquantel topical solution) for New World Screwworm (NWS) for cats.
Afoxolaner, the active ingredient in NexGard, and esafoxolaner, one of the active ingredients in NexGard Combo, belong to a class of antiparasitic drugs called isoxazolines. Although isoxazoline products are commonly used and safe for most pets, the products have been associated with neurologic adverse reactions, including muscle tremors, ataxia, and seizures. Pet owners should consult with a veterinarian to determine whether NexGard or NexGard Combo may be appropriate for their pet.
In addition to the EUA, NexGard chewable tablets are FDA-approved for flea and tick-related indications in dogs and puppies. NexGard COMBO topical solution is FDA-approved for flea, tick, and worm-related indications in cats and kittens.
NexGard and NexGard COMBO are sponsored by Boehringer Ingelheim Animal Health USA, Inc. based in Duluth, Georgia.
Related Information
NexGard for Dogs
Freedom of Information Summary: NexGard (EUA 006685)
Letter of Authorization: NexGard (EUA 006685)
Fact Sheet for Veterinarians: Emergency Use Authorization of NexGard (afoxolaner) Chewables for New World Screwworm (NWS)
NexGard COMBO for Cats
Freedom of Information Summary: NexGard COMBO (EUA 006686)
Letter of Authorization: NexGard COMBO (EUA 006686)
Fact Sheet for Veterinarians: Emergency Use Authorization of NexGard COMBO (esafoxolaner, eprinomectin, and praziquantel topical solution) for New World Screwworm (NWS)
Fact Sheet for Pet Owners and Veterinarians about Potential Adverse Events Associated with Isoxazoline Flea and Tick Products
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