FDA expands Bravecto Quantum label for two additional tick species

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Merck Animal Health has won an FDA label expansion for Bravecto Quantum, adding 12-month treatment and control claims in dogs for Asian longhorned tick (Haemaphysalis longicornis) and Gulf Coast tick (Amblyomma maculatum). The company announced the approval on March 18, 2026, framing it as a broader parasite-control profile for its veterinarian-administered injectable fluralaner product. The update builds on Bravecto Quantum’s original July 10, 2025 FDA approval as the first long-acting flea and tick treatment for dogs in the U.S. (merck-animal-health.com)

That original approval was notable because it introduced an 8- to 12-month protection window in a single injection, but the duration depended on the tick species involved. FDA said at the time that the product must be prescribed by a licensed veterinarian because professional expertise is needed not only to administer the injection and monitor for adverse reactions, but also to determine the appropriate treatment interval based on which ticks a dog is likely to encounter. That nuance has stayed important, especially as Bravecto Quantum has been marketed as a once-yearly option. (fda.gov)

With the new label, Bravecto Quantum now carries 12-month claims against Asian longhorned tick, Gulf Coast tick, black-legged tick, American dog tick, and brown dog tick after a single injection. Protection against lone star tick remains 8 months, not 12. That distinction has drawn outside scrutiny: earlier this month, the Better Business Bureau’s National Advertising Division said Merck had support for describing the product as a safe, effective year-round option, but recommended the company discontinue or modify unqualified “once a year” tick-protection claims because dogs with potential lone star tick exposure require an 8-month dosing interval under the FDA-approved labeling. Merck has appealed parts of that decision. (merck-animal-health.com)

The added species matter because both are part of a changing tick landscape in the U.S. FDA’s 2024 FOI summary for Bravecto 1-Month described the Asian longhorned tick as a new U.S. species first reported here in 2017. USDA says U.S. populations are parthenogenetic, meaning females can reproduce without mating, a trait that can accelerate establishment and spread. Gulf Coast tick, meanwhile, has historically been associated with the Southeast, but CDC researchers reported established populations in parts of the Northeast and noted the species’ relevance for human and animal health. PubMed-indexed research cited by public health agencies identifies Gulf Coast tick as the primary vector of Rickettsia parkeri and Hepatozoon americanum, the latter causing American canine hepatozoonosis. (animaldrugsatfda.fda.gov)

Merck’s public messaging around the expansion has emphasized convenience and breadth of coverage. In its release, the company said the updated indication reinforces Bravecto’s position as the longest-lasting flea and tick protection available for dogs in the U.S. Company executives also cast the expansion as a response to clinically important tick species. Independent commentary has been more measured, focusing on label precision rather than disputing the product’s underlying efficacy. The NAD decision is the clearest recent industry reaction, underscoring that the practical meaning of “year-round” depends on local parasite exposure and the species on the label. (merck-animal-health.com)

Why it matters: For veterinarians, this is less about a brand milestone than about protocol design. The broader label could make Bravecto Quantum more useful in practices seeing shifting tick geography, especially in regions where Asian longhorned tick or Gulf Coast tick are emerging concerns. It may also help clinics reduce adherence gaps among pet parents who struggle with monthly or every-12-week preventives. But the product still requires species-aware counseling: a dog in lone star tick territory may not be on a true 12-month interval, even if the same product covers other ticks for a full year. That makes local epidemiology, travel history, and clear client communication central to appropriate use. (fda.gov)

Safety and administration considerations also remain part of the conversation. FDA said at the original approval that Bravecto Quantum should only be prescribed by a licensed veterinarian because administration and follow-up require professional oversight. Merck’s prescribing information lists commonly reported adverse reactions in a U.S. field study as lethargy, decreased appetite, vomiting, diarrhea, elevated liver enzymes, and pruritus. As with other isoxazolines, case selection and informed discussion with pet parents remain important, particularly when teams are considering a long-duration injectable product that cannot simply be discontinued once administered. (fda.gov)

What to watch: The next question is whether this expanded label changes clinic uptake in tick-heavy markets and how prominently practices position Bravecto Quantum in preventive care plans for 2026. It’s also worth watching whether Merck’s appeal in the NAD case changes how year-round claims are presented, because that dispute goes directly to how veterinary teams and pet parents interpret “once-yearly” protection in real-world tick environments. (bbbprograms.org)