Bravecto for Dogs: How Does It Work & Is It Safe?



Ben Team


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All owners should employ an appropriate flea and tick prevention strategy to keep their pet healthy and happy. Fleas are not only irritating to dogs, they can lead to serious health problems if left unchecked.

Ticks are an even bigger issue, as they can transmit deadly diseases to you and your pet.

In the old days, there weren’t very many great ways to keep fleas and ticks off your pet. There were a few sprays designed to kill fleas and you could fit your dog with a flea collar, but neither of these strategies was especially effective.

Fortunately, modern dog owners have their choice of several different products that kill or repel biting bugs. Preventative medications, which protect your dog from fleas and ticks for weeks or months at a time, are some of the most effective and popular products modern owners use.

We’ll talk about one such flea and tick medication – Bravecto – below, so you can start figuring out if it is a good option for your pooch.

What is Bravecto?

Bravecto is a flea-and-tick medication that uses the active ingredient fluralaner — a systemic ectoparasiticide (meaning that it kills bugs that live on the outside of your dog’s body).

Bravecto comes in two forms: a flavored, chewable tablet that most dogs find palatable and a topical liquid.

How Long Does Bravecto Last?

The tablet provides three months of protection against fleas and ticks, while the topical treatment is effective for four months against ticks and six months against fleas. 

Bravecto is known to kill the following parasites:

  • Fleas
  • Black-legged ticks
  • American dog ticks
  • Brown dog ticks
  • Lonestar ticks

It is capable of killing all of these bugs for 12 or 16 weeks (depending on whether you use the tablet or topical treatment, respectively), except Lonestar ticks. It is only effective at killing Lonestar ticks for eight weeks. 

Fluralaner may provide some protection against mosquitos, but it appears to be less effective than other drugs (such as fipronil) in such contexts. It also appears to be effective for treating demodectic mange.

The medication comes in five different dosages, which are suitable for dogs of different sizes. It can be administered to puppies who are at least 6 months of age.

Bravecto was first approved for use in the United States and Europe in 2014.

How Does Bravecto Work?

Fluralaner – the active ingredient in Bravecto – works like many other flea and tick medications do.

If you use the oral version, you simply give your dog one of the tablets. His body will then start breaking down the tablet, allowing the fluralaner present in the medication to make its way into your dog’s bloodstream.

If you use the topical form of the drug, the medication penetrates your dog’s skin, where it mixes with the fluids underneath.


Fluralaner inhibits the nervous systems of arthropods (joint-legged animals, including fleas and ticks), so when a flea or tick bites your dog, it becomes exposed to the drug and dies in short order.

Fluralaner is in the isoxazoline class of drugs, along with other common flea and tick medications, such as afoxolaner (NexGard) and sarolaner (Simparica).

What are the Side Effects of Bravecto for Dogs? Is It Safe? Have Dogs Died?

Bravecto has been popping up in the news quite a bit over the last few years and, unfortunately, it’s been receiving this coverage for pretty disturbing reasons.

Specifically, it appears to have sickened a number of dogs – it’s even been implicated in a number of pet deaths.

But before we jump to any hasty conclusions, let’s look at some of the facts.

Empirical Studies of Bravecto/Fluralaner

Fluralaner has been studied in a number of empirical studies, including the following:

  1. Safety of Fluralaner Chewable Tablets (Bravecto), a Novel Systemic Antiparasitic Drug, in Dogs after Oral Administration

This study investigated the safety of orally administered fluralaner in treating fleas and ticks. The study determined that the medication was largely safe, and that the drug has a safety margin of more than five (meaning that dogs could tolerate five times the recommended dose) in healthy dogs who were at least 8 weeks of age and 2 kilograms (about 5 pounds).

  1. Safety of Fluralaner, a Novel Systemic Antiparasitic Drug, in MDR1(-/-) Collies after Oral Administration

Many herding breeds have a genetic mutation, which often makes them unable to tolerate ivermectin and several other flea and tick medications. This study investigated whether or not collies with this mutation could safely tolerate fluralaner. The study concluded that the medication was, in fact, well tolerated by collies who possessed the mutation.

  1. A Randomized, Blinded, Controlled and Multi-Centered Field Study Comparing the Efficacy and Safety of Bravecto™ (Fluralaner) against Frontline™ (Fipronil) in Flea- and Tick-Infested Dogs

This study sought to compare fipronil with fluralaner to determine which one was more effective at killing fleas and ticks. The data demonstrated that fluralaner was as good at killing ticks and better at killing fleas than fipronil.

  1. The novel Isoxazoline Ectoparasiticide Fluralaner: Selective Inhibition of Arthropod γ-Aminobutyric Acid- and l-Glutamate-Gated Chloride Channels and Insecticidal/Acaricidal Activity

This study basically illustrated the chemical nature of fluralaner and described its method of action. This is pretty dense material, but we’ve included it for any readers who may be interested.

  1. Efficacy of Orally Administered Fluralaner (BravectoTM) or Topically Applied Imidacloprid/Moxidectin (Advocate®) against Generalized Demodicosis in Dogs

This study sought to determine if fluralaner is effective for treating demodectic mange in dogs. The results of the study suggest that it is effective for doing so.

  1. The Effect of Food on the Pharmacokinetics of Oral Fluralaner in Dogs

This study investigated how food affected the absorption of fluralaner in dogs. According to the study, the medicine is well-absorbed in fed or fasted dogs, but it was more bioavailable when administered to dogs who’d recently eaten.

  1. Fluralaner, a Novel Isoxazoline, Prevents Flea (Ctenocephalides felis) Reproduction in Vitro and in a Simulated Home Environment

This study investigated the efficacy of fluralaner in killing fleas. The data collected showed that the drug is very effective at killing fleas, and it even prevented fleas from reproducing at sub-insecticidal (non-lethal) concentrations.

Documented Bravecto Side Effects

It is important to understand that companies producing medications must investigate the potential side-effects they cause before entering the market or being approved for use.

According to the product information published by Merck, the topical version of the drug caused the following side effects in a controlled study:

  • 3% if the dogs in a study experienced vomiting after taking the medication. However, 6% of the dogs in the control group also experienced vomiting during the study.
  • 1% of the dogs administered Bravecto suffered hair loss (alopecia). This contrasts with 2% of the dogs in the control group who lost hair without being given the medication.
  • 7% of the dogs given Bravecto suffered from diarrhea, but 11% of the dogs who weren’t given the medication suffered from diarrhea.
  • 7% of the dogs given Bravecto exhibited lethargy, compared with 2% of the dogs in the control group who exhibited the same problem.
  • 4% of the dogs given Bravecto appeared to lose their appetite, while none of the dogs in the control group did.
  • 9% of the dogs who were given Bravecto developed a rash, while none of the dogs in the control group did.

Merck also studied the way dogs tolerated the oral version of the drug too. In many respects, the results were similar to those obtained from studying the topical version.

  • Vomiting occurred in 7.1% of the dogs given Bravecto, and in 14.3% of the animals in the control group.
  • 7% of the dogs given Bravecto experienced a diminished appetite, compared with 0% of the dogs in the control group.
  • Diarrhea occurred in 4.9% of the dogs given Bravecto and 2.9% of those in the control group.
  • 8% of the dogs given the medication experienced excessive thirst, but the same issue was seen in 4.3% of the dogs in the control group.
  • Flatulence was reported in 1.3% of the dogs given Bravecto and none of the dogs in the control group (I’d like to know where they found these fart-free dogs).

Merck also discloses that seizures have been reported in dogs administered fluralaner. However, I was only able to find one reference to seizures in their detailed literature.

According to the data above (which, it should be noted, is all courtesy of Merck), there are some side effects that have been documented following the use of Bravecto. However, it is important to review the data from the control group too.

This is an important consideration, as a few dogs in any given group will suffer from normal ailments like vomiting and diarrhea. By considering both the experimental and the control group, you can often get an idea of how likely it was that the drug caused the ailment.

For example, if you look carefully, you’ll note that 11% of the dogs in the control group of the topical trial suffered from diarrhea. Meanwhile, only 2.7% of the dogs who were treated with Bravecto suffered from intestinal issues.

This doesn’t mean that Bravecto prevented these dogs from having diarrhea, but it does suggest that the medication is not terribly likely to cause diarrhea in dogs.


Bravecto Anecdotal Reports

Anecdotes don’t have the same value as empirical studies, but they are still important to consider. And unfortunately, there are a number of very troubling anecdotal reports associated with fluralaner.

Many owners have reported that they believe fluralaner was responsible for triggering seizures or vomiting in their pet. Some have even reported that their dog died after being administered the medication.

WSB-TV consumer investigator Jim Strickland has started collecting these reports, speaking with vets and owners, and trying to get a response from Merck (the manufacturer of the drug) about the issue. According to Strickland, he has received “hundreds” of reports implicating fluralaner in the deaths of dogs. Additionally, European regulators have collected approximately 800 reports of pet deaths worldwide.

However, Strickland has also spoken to at least one vet who praised the drug’s safety and mentioned that this was one of the drug’s selling points. One veterinary office has administered 3,400 individual doses of the drug without a single complaint.

Merck representatives have so far declined to comment on the issue.

The Takeaway: Weighing Anecdotal Reports against Empirical Studies

So, what is a pet owner to do? Do you rely on the empirical studies and manufacturer’s data that suggest fluralaner is safe, or do you rely on the anecdotal reports from owners who believe fluralaner has sickened or killed their pets?

You’ll just have to discuss the issue with your vet and make the best decision you can. We can’t tell you the proper path for your dog.

However, there are two things I’d encourage you to consider when making your decision.

1. Just because an owner thinks that fluralaner killed his or her pet, doesn’t mean it did.

I have yet to find any reports from vets or pathologists indicating that fluralaner has been conclusively demonstrated to cause death in pets (please share them with us in the comments, if you are aware of any).

Vomiting and seizures are both known, but rare, side effects, but I’ve yet to find a report from a vet that clearly linked fluralaner with a dog’s death.

It is also entirely possible that any deaths that did occur were associated with improper dosages or interactions with other health conditions or medications in play.

2. When reviewing empirical studies, always note the associations of the authors.

I’m a pretty science-minded guy and I try to embrace a skeptical mindset as much as possible (note that I said skeptical, not cynical – they’re two different things). So, I tend to look for peer-reviewed studies when I’m trying to get to the truth of a situation. When I began researching fluralaner, it appeared that there was plenty of science that backed the drug’s efficacy and safety.

But then I noticed something pretty troubling: In each of the seven studies discussed above, one or more of the authors is an employee of MSD Animal Health. In several cases, all of the authors were employees of MSD Animal Health. Why does this matter?

MSD Animal Health is a subsidiary of – wait for it – Merck.

Now, before you bust out your tinfoil hat, let’s be clear: Just because a scientist is employed by a company that manufactures the drug he or she is researching doesn’t mean the data collected is invalid.

It is entirely possible (perhaps even likely) that all of the scientists involved in these studies are completely aboveboard and carried out their research in the best possible way. And for that matter, the referenced studies were all randomized and blinded, which drastically reduces the chances for bias to show up. 

Also, MSD has a financial interest in performing research, so it isn’t necessarily surprising that they’ve conducted most of the studies I found. 

But it’s also not the kind of thing to ignore completely. After all, there’s a reason reputable journals force authors to acknowledge any potential conflicts of interest.

Bravecto for Dogs

Bravecto For Puppies: Is It Safe for Young Dogs?

According to the data available, Bravecto appears safe for use in puppies.

Merck recommends only using the drug on puppies who are at least 6 months of age and at least 4.4 pounds in weight. However, they also point to studies that demonstrate that puppies of 8 to 9 weeks were able to tolerate up to five times the typical dosage.

Additionally, Merck states that Bravecto is safe for breeding, pregnant, and lactating dogs.

Bravecto Without Vet Prescription: Can I Get It Myself?

Currently, Bravecto is only available with a prescription from your vet. Frankly, this is a bit puzzling, as the medication has no known contraindications, and most of the clinical trials have shown that it is quite safe.

In fact, it even appears to be safe for collies that are MDR-1 gene deficient (dogs with this genetic mutation are unable to safely take some other flea and tick products). Additionally, the medication is classified as safe for puppies and mothers who are lactating or pregnant.

Nevertheless, you’ll need to obtain a prescription from your vet to legally purchase and administer this medication to your dog.

Bravecto Rebate: Are There Any Rebates Associated with Bravecto?

Merck offered a rebate program for Bravecto for most of 2018, and it appears they offered similar rebate programs in earlier years too. But unfortunately, we were unable to find any rebate program that is still effective in 2019.

That doesn’t mean Merck won’t re-institute a rebate program in the future. They may even be willing to provide one if you simply call and ask – it certainly won’t hurt to try.

Where to Buy Bravecto for Dogs

There are a number of places you can purchase Bravecto for your dog. Many vets will sell the medication to you when they prescribe it, but you can often find the best prices online. is likely the best place to buy Bravecto. They offer the topical and oral version of the drug, and they stock it in doses appropriate for dogs of all sizes.

Note that you’ll still need to obtain a prescription to purchase Bravecto, no matter where you (legally) purchase it from. You’ll need to submit proof of your prescription when ordering, and then a member of Chewy’s staff will verify the prescription and process your order.


At the end of the day, there’s a lot to like about Bravecto, but there are also some things that may give owners pause. Ultimately, you’ll need to discuss the issue with your vet and make the best decision you can on behalf of your pet.

Have you ever used Bravecto for your dog? Did he tolerate the medicine well? Did it prove to be effective at killing fleas and ticks? Let us know all about your experiences in the comments below.

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Written by

Ben Team

Ben is the managing editor for K9 of Mine and has spent most of his adult life working as a wildlife educator and animal-care professional. Ben’s had the chance to work with hundreds of different species, but his favorite animals have always been dogs. He currently lives in Atlanta, GA with his spoiled-rotten Rottweiler named J.B. Chances are, she’s currently giving him the eyes and begging to go to the park.

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  1. Rein Avatar

    I have been using the topical solution for my cat Carrot (age 7), and the chewable tablet for my pit bulls Killer (age 2) and Fauna (age 9) for 5 years now (only about 1 and a half or so for killer, she started at abouy 6 or 7 months) and I havent seen any issues. Fauna doesn’t like to eat for about 12ish hours after eating the tablet, so we make sure she eats beforehand. Both puppers love the tablets so when i come home from the vet with them it becomes treat time. I get the feeling that claims to dog deaths may be due to other factors that arent being considered, such as age, breed specific problems, previous illnesses or conditions, etc. I wont sit here and say no dogs died because of it since i dont know for sure either way. But people can be quick to fully blame something without further proper research.

    1. Ben Team Avatar

      Glad it’s worked well for you and your pups, Rein. Thanks for sharing!

  2. Angela Hitch Avatar
    Angela Hitch

    How does Bravecto prevent Lyme disease if the tick has to bite the dog before it does? I understood bites from infected ticks cause Lyme disease.

    1. Ben Team Avatar

      Hey, Angela.

      I don’t think that it’s been conclusively demonstrated that Bravecto will prevent Lyme disease. Most authorities use language like “it’s expected to prevent Lyme disease.”
      In other words, it probably reduces the likelihood of your pet contracting Lyme (or other tick-vector diseases), but it’s unlikely to be an infallible forcefield.

      Ticks likely require some time to transmit Lyme disease. If they die within minutes of biting your pet, they just won’t have enough time to spread germs to your dog. Many tick-borne diseases require the tick to remain attached for a significant length of time to spread a disease, so Bravecto just tries to kill the ticks before this can happen.

      Hope that helps! Be sure to check out our guide to the best tick treatments to see a few other options.

  3. Alam William Avatar
    Alam William

    Thankyou to keep us informing about bravecto Chews for dogs, the soft tablates are canine fav. its a great treat that also effective on Flea and Tick.

  4. Toni Avatar

    Bravecto and Nexguard are not safe to use. In June of 2018 my dad gave our 9 year old Foxhound mix MJ her first dose. Bare in mind before given this crap she was perfectly healthy. In August I noticed she was starting to lose her balance. I lived in a city two hours from my parents and had to return to work. I came home in October for Thanksgiving. I noticed she was getting worse. I took her for a walk one day. She saw our neighbour and ran to greet him. She fell in his driveway scraping her chin and sprung her back leg. Emergency trip to the vet. I had to return home for work. By the time I came back at Christmas she could no longer walk. January 2nd 2019 we said our final goodbyes. You may think my story is rare and few between. It is not there are hundreds if not thousands of people in groups on Facebook with similar stories or stories of their dogs reacting but getting Veterinary care in enough time. This crap needs to be removed from the market.

    1. Alison Avatar

      Horrible to lose your dog in this way, but these symptoms did not appear until a considerable time after the bravecto was given. If you google ‘foxhound medical issues’ I think you will find that there are at least a couple of conditions that might explain these symptoms.

  5. Lindsey Avatar

    I switched to Bravecto for my dog based on recommendations from vet and people I know who already used it. We’ve been using it since mid-2017 and haven’t had any issues yet. I appreciate how this article breaks down the pros and cons and uses as much scientific data as possible.

  6. Louiseodonnell Avatar

    I gave my dog bravecto(tablet) in the afternoon.from 3am vomiting and diarrhoea.this lasted for 2 days.she was off her food and slept most of the 3rd day ok but very smelly wind.

  7. Patty Turner Avatar
    Patty Turner

    14 month old chocolate lab and works great!!! No side effects at all. Just wish it wasn’t so expensive. $62 at my vet.

  8. Jitka Avatar

    Hello, as an owner of four Siberian Huskies, external parasites are of an issue. I do not usually opt to medicate the dogs unless its really necessary. In the past, I have used topical medications such as Frontline with moderate success; however, my dogs are frequently groomed for dog shows and the topical agents do not work as well with frequent grooming. Also, I noted, the frontline causes staining. During the times that ticks are really bad, I refrain from taking the dogs into the woods and stick to town parks and paved paths for walks. This year the tick infestation is especially bad; I decided to try Bravecto in one of my dogs. Its been 5 days since the administration. The dog did not exhibit any symptoms of GI upset, skin issues, or loss of appetite. However, he does present with unusual calmness. Overall, very effective product for killing of ticks so far.

    1. Ben Team Avatar

      Good to hear it’s worked for your pups, Jitka. Keep us updated!

    2. Ben Team Avatar

      Good to hear it’s worked for your pups, Jitka. Keep us updated!

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