Pet owners blame flea and tick medicine for their dogs' deaths

    Pet owners call for further review of flea and tick medicine


    COLUMBUS, Ohio — The U.S. Food and Drug Administration is alerting pet owners and veterinarians that some flea and tick medications can cause adverse reactions in dogs and cats.

    Some animals receiving drugs in the isooxazoline class have experienced adverse events such as muscle tremors, ataxia, and seizures, according to the FDA.

    The medicine includes Bravecto, Nexgard, and Simparica. Another product in this class is Credelio, which recently received FDA approval. The FDA says these products are approved for the treatment and prevention of flea infestations, and the treatment and control of tick infestations.

    If your dog or cat experiences and adverse reaction, they say you should contact your veterinarian.

    To report suspected adverse drug events for these products and/or obtain a copy of the Safety Data Sheet (SDS), or for technical assistance, you can contact the manufacturer(s):

    Merck Animal Health (Bravecto): 800-224-5318

    Elanco Animal Health (Credelio): 888-545-5973

    Merial (Nexgard): 888-637-4251

    Zoetis (Simparica): 888-963-8471

    FDA warning:


    In February of 2017, ABC3340 first reported on concerns about certain flea and tick medications. Our story focused on Bravecto.

    BIRMINGHAM, Alabama - growing number of pet owners are demanding an investigation into a popular flea and tick medication. Since Bravecto hit the market in 2014, 34 million doses have been dispensed for dogs and cats. But some believe it's lead to serious side effects and in some cases deaths.

    Fighting For You looked into those safety claims. Alyson Griffin of Hokes Bluff says four month old Ringo was prescribed Bravecto to treat a common skin irritation, but with in 24 hours he started getting sick. "Something was wrong; he stopped eating; couldn't drink anything," explains Griffin.

    As his condition got worse, her husband held Ringo and they headed to the vet. "As he was walking toward door Ringo had a seizure and died right there in his arms. It was really emotional," says Griffin.

    The vet found little Ringo full of fluid; his organs had failed. "Bravecto is the only thing we had tried differently that would have been a possibility to cause this," says Griffin. An online search of the drug led them to a Facebook page called "Does Bravecto Kill Dogs?" It has more than 34,000 followers.

    "Story after story sounded so much like what happened to Ringo," comments Griffin.

    Sandy Taylor of Pell City shares a similar story. Her nine year old dog got terribly sick after one dose. "Gabby became lethargic and wouldn't drink or eat much," explains Taylor. She says the only different thing they had done was give her the flea pill. Gabby died a week later. She and others say the product needs more independent investigation.

    Both Taylor and Griffin now wish they had requested a necropsy which is an animal autopsy to determine exactly what went so wrong.

    "If it's unsafe we need to know. But the data out there right now shows it's an extremely safe product," says Veterinarian Ken McMillan. He is Taylor's vet and believes Gabby's death was due to diabetes.

    He worked on the clinical trials for Bravecto and says with any drug there can be side effects. But his work found far fewer bad reactions with Bravecto. He gives the medication to his own pets.

    He says given orally it has advantages because it won't rub off or wash off and is very effective.

    But the heartache and the questions remain for the families. "It just broke our heart," says Griffin.

    The manufacturer, Merck Animal Health, says 55 clinical research trials were done on Bravecto before it was approved for market. The company says adverse reactions were rare and serious problems were very rare. The most common side effect was vomiting.

    If your pet has a reaction to any medication call your vet and be sure it is reported. Also consider that post mortem testing, which is the only way to get some definitive answers.

    For information on adverse drug experience reporting contact the FDA:



    Complete statement from Merck Animal Health:

    As veterinarians and/or pet owners ourselves, those of us at Merck Animal Health do what we do because of our love for animals. We understand the significant bond between pets and their owners and an animal’s health and well-being is our top priority. We know that veterinarians and pet owners look to us to provide accurate and balanced information about our products, which is why it is so important that we share the facts about Bravecto.

    The safety of Bravecto has been documented in more than 55 clinical research trials. These clinical trials were the basis for the approval of Bravecto by 72 regulatory agencies around the world. Each of these regulators has affirmed that the product is safe and effective for use as indicated in the label.

    In addition, we have conducted and continue to conduct a range of post-approval research work including safety and efficacy. To date, more than 34 million doses of Bravecto have been dispensed since it was first approved for sale in 2014. With regard to these 34 million doses, we have monitored the safety of Bravecto through extensive post-marketing surveillance. Our post-approval studies and post-approval surveillance have provided additional compelling evidence that supports the safety profile of Bravecto.

    We report all adverse events to the governing regulatory agency whether they were linked to the product or not. We do this not only because it is a legal requirement but so that accurate safety and efficacy information is available for veterinarians prescribing our products. It is important to note that a report does not equal causation.

    Once we have submitted adverse events, the European Medicines Agency (EMA) and regulatory agencies around the world, including FDA, conduct reviews of the adverse event reports. Based on the most recent Periodic Safety Update Report (PSUR) assessed by EMA, the incidence of all adverse events remains categorized as “rare”, which means occurring in between 1/10,000 and 1/1,000. The most common reported events are mild and transient gastrointestinal upset, which are noted on the product label.

    As is the case with nearly any product, we also receive reports of serious adverse events. For Bravecto, the incidence of such events is in line with the “very rare” (less than 1/10,000) categorization – which is the most rare form of categorization available to EMA. Moreover, such “very rare” adverse events may be related to underlying disease, other medications used at the same time, inappropriate use, and many other factors. Notwithstanding their “very rare” incidence, we take very seriously every report, regardless of whether there is any basis to believe the event may be related to Bravecto or not.

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