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Is Bravecto Safe for Dogs and Cats?

📅 Updated February 2026⏱️ 5 min readNEW

TL;DR

Bravecto is highly effective but comes with a serious FDA warning for neurological adverse events. While safe for the majority of pets, it has been linked to muscle tremors, ataxia, and seizures—even in animals with no prior history. For a safer chemical alternative, older topicals like Frontline Plus do not carry this specific seizure risk.

🔑 Key Findings

1

FDA issued a warning in 2018 (and updated it since) linking isoxazoline drugs like Bravecto to neurological events.

2

Adverse reactions include vomiting, lethargy, and in rare cases, seizures and tremors.

3

Community surveys suggest adverse event rates may be higher than the '1 in 10,000' official estimate.

4

Topical non-isoxazoline treatments (like Frontline) do not carry the same neurological warnings.

The Short Answer

Bravecto is effective but risky. While it is one of the most convenient options—lasting 12 weeks per dose—it belongs to a class of drugs called isoxazolines, which the FDA explicitly warns can cause neurological adverse events like muscle tremors, loss of balance (ataxia), and seizures.

Most pets take it without issue, but the risk is real. The FDA states that seizures may occur in animals without a prior history of them. If your dog has a history of seizures, you should avoid Bravecto entirely. For healthy pets, it remains a "use with caution" product where you must weigh the convenience against the potential for rare but serious side effects.

Why This Matters

The "convenience at a cost" trade-off is central here. Bravecto works by putting a pesticide (fluralaner) into your dog's bloodstream. When a flea or tick bites your dog, it ingests the poisoned blood and dies. This systemic mechanism is exactly why it works so well—and exactly why it causes concern.

There is a significant gap between "official" and "community" data. Manufacturer studies often cite serious adverse events as "rare" (less than 1 in 10,000). However, independent surveys like "Project Jake" have reported much higher rates of adverse reactions among users. This discrepancy suggests that while "death" is rare, quality-of-life side effects like lethargy and stomach upset may be underreported.

Crucially, not all chemical treatments are the same. Older topical treatments like Frontline (fipronil) do not enter the bloodstream in the same way and do not carry the FDA's isoxazoline seizure warning. You have chemical options that don't involve risking your pet's neurological health.

What's Actually In Bravecto

Bravecto relies on a powerful insecticide that works systemically.

  • Fluralaner — The active ingredient. It is an isoxazoline, a class of pesticides that inhibits the nervous system of insects. The concern is that it can inadvertently affect the GABA receptors in mammals (your dog), potentially leading to neurological misfires. Is Simparica Trio Safe
  • Hydrolyzed Pork — The flavoring used in the chews. While generally safe, this can trigger issues in dogs with severe food sensitivities, though it is hydrolyzed to reduce allergic response.
  • Magnesium Stearate & Glycerol — Common binders and stabilizers. Generally safe but "filler" ingredients.

What to Look For

Green Flags:

  • Topical Application — Treatments that stay on the skin (like Frontline) generally have lower systemic risks than oral pills.
  • Natural Actives — Cedarwood oil, peppermint oil, and lemongrass oil are proven repellents that don't carry neurological risks. Natural Flea Tick Prevention Dogs

Red Flags:

  • Isoxazoline Class — Any product containing fluralaner, afoxolaner (NexGard), sarolaner (Simparica), or lotilaner (Credelio). Is Nexgard Safe
  • "Oral" Pesticides — Any pest control that requires the poison to be in your pet's blood means the chemical is circulating through their liver, kidneys, and brain.
  • History of Seizures — If your pet has ever had a seizure, do not use Bravecto.

The Best Options

If you need chemical efficacy without the seizure risk, older topicals are often a safer bet. If you want to avoid chemicals entirely, rigorous natural prevention is key.

BrandProductVerdictWhy
WondercideFlea & Tick SpraySafe, natural, effective repellent. Requires frequent application.
FrontlinePlus for Dogs⚠️Chemical but safer. Topical (not systemic) and no seizure warning.
BravectoChews / Topical⚠️High efficacy, but FDA warning for seizures and tremors.
SerestoCollar🚫Effective but linked to chemical burns and high rates of adverse reports.

The Bottom Line

1. Avoid if susceptible. If your dog has a history of seizures, tremors, or neurological issues, do not use Bravecto. The risk is explicitly documented by the FDA.

2. Consider topicals first. If you need a heavy-duty chemical killer (e.g., you live in a high-tick area), older topicals like Frontline Plus treat pests without the same systemic neurological risks.

3. Use natural for prevention. For low-risk areas or everyday prevention, natural cedar-based sprays like Wondercide are safe and effective repellents, though they don't kill "on contact" as aggressively as oral poisons.

FAQ

Does Bravecto cause seizures?

Yes, it can. The FDA issued an alert stating that isoxazoline drugs (including Bravecto) have been associated with muscle tremors, ataxia, and seizures. While most dogs are fine, these events can happen even in dogs with no prior history of seizures.

Is the Bravecto topical safer than the chew?

Not necessarily. Both contain the same active ingredient, fluralaner. While the topical might bypass the digestive system (reducing vomiting risk), the drug is still absorbed through the skin into the bloodstream to work systemically. The FDA warning applies to the entire isoxazoline class, regardless of form.

Can I use Bravecto for my cat?

Only the cat-specific topical. Never give a dog chew to a cat. The topical version for cats also contains fluralaner and carries the same potential neurological risks. Cats can be particularly sensitive to muscle tremors and ataxia from this drug class.

How long does Bravecto stay in their system?

12 weeks. This is its main selling point but also a drawback. If your pet has a bad reaction, you cannot simply "stop" the medication—it will remain active in their body for three months. Monthly pills (like NexGard) or topicals clear the system faster.


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