FDA expands Bravecto Quantum tick label in dogs

Merck Animal Health has won an FDA label expansion for Bravecto Quantum, adding 12-month treatment and control claims in dogs for the Asian longhorned tick and Gulf Coast tick. The March 18, 2026 update extends the reach of a product that was already notable as the first FDA-approved long-acting flea and tick treatment for dogs, administered as a veterinarian-delivered subcutaneous injection rather than a monthly chew or topical. (merck-animal-health.com)

Bravecto Quantum first entered the U.S. market on July 10, 2025, with approval for dogs and puppies 6 months of age and older. At launch, FDA said the product provided 8 to 12 months of protection, depending on the parasite involved, and stressed that it must be prescribed and administered by a licensed veterinarian because professional judgment is needed to select the correct retreatment interval, monitor for adverse reactions, and advise pet parents, including those with breeding dogs. (fda.gov)

With the new label, Merck says Bravecto Quantum now covers Asian longhorned tick and Gulf Coast tick for 12 months, in addition to its existing 12-month claims for fleas, black-legged tick, American dog tick, and brown dog tick. One important detail hasn’t changed: lone star tick coverage remains 8 months, not 12. That distinction matters operationally for clinics because it affects recall timing, regional parasite recommendations, and how teams frame “annual” protection in client conversations. (merck-animal-health.com)

The broader tick list comes as veterinarians and public health agencies continue tracking changes in tick distribution. CDC notes the Asian longhorned tick is established in multiple U.S. areas, and recent veterinary reporting has highlighted new state detections, including a dog-associated finding in Kansas in late 2025. The Gulf Coast tick also carries veterinary and public health relevance because it is the recognized vector of Rickettsia parkeri, a cause of spotted fever rickettsiosis in people. For practices in endemic or expanding-risk regions, added labeled coverage may be clinically and commercially meaningful. (cdc.gov)

On safety, the FDA’s original approval materials and Merck’s current release are broadly aligned: Bravecto Quantum is an isoxazoline, and that class has been associated with neurologic adverse reactions, including tremors, ataxia, and seizures in some dogs. In the FDA freedom-of-information summary, one dog in a margin-of-safety study had seizures and polyarteritis considered possibly drug related, while Merck’s release says 0.9% of dogs in a U.S. field study experienced seizures, a rate the company says is consistent with estimates in the general dog population. That means the product’s convenience story still sits alongside the same careful case selection and counseling that apply to other isoxazolines. (animaldrugsatfda.fda.gov)

There’s also a messaging issue hanging over the brand. In March 2026, BBB National Programs’ National Advertising Division said Merck had support for certain safety claims, but recommended the company discontinue or modify ads implying that a single injection provides a full year of tick protection for dogs generally. The reason: FDA-approved labeling requires an 8-month dosing interval for dogs with potential exposure to lone star ticks. Merck has appealed parts of that decision. For veterinarians, that dispute is a reminder that the product’s value proposition is real, but species-specific nuance can’t be glossed over. (bbbprograms.org)

Why it matters: For veterinary professionals, this approval is less about a brand-new product than about a more complete label for a product that could reshape compliance discussions. A veterinarian-administered injectable can reduce gaps tied to missed monthly dosing, and the newly added tick claims may increase the product’s fit in regions where Asian longhorned tick or Gulf Coast tick exposure is part of the risk picture. But clinics will still need clear protocols for identifying likely tick exposure, documenting why an 8- versus 12-month interval was chosen, and counseling pet parents on adverse-event risk, especially in dogs with seizure histories or neurologic concerns. (fda.gov)

What to watch: The next step is market uptake and implementation: whether practices add Bravecto Quantum more broadly to preventive care workflows, whether Merck updates promotional language in response to the NAD case, and whether future field data further define how the product performs across different geographies, tick pressures, and patient populations. (bbbprograms.org)