Trifexis: Is it really killing dogs?

The short and quick answer is NO! This is to respond to the report done by WSB-TV in Atlanta. This report has caused scare and anxiety among many clients that have given this product for a long time.

First- The puppies that were littermates that died had inflammation around the heart. The cause of death was tied more to a bacterial infection as opposed to lesions seen with a toxicity.

Second- The older dog that died had some evidence of a possible lung mass before it died. The owners declined a necropsy so we will not have any better idea of what led to this dog’s death.

When discussing the adverse reactions to the drug, the reporter said some 2,000 dogs had cases of vomiting. That’s a lot of vomiting after taking a medication. The drug, however, warns if the pill is not given with a full meal, it will cause your pet to vomit! Just like how our human doctors tell us to take a medication with a meal, we have to give some medications to our pets with a full meal.

In the follow up the reporter spoke with a vet in the community. The vet supposedly said he has prescribed the product but prefers others. The report did not say why he prescribed other products. I would have preferred for the reporter to find a vet that uses Trifexis and hasn’t seen any issues, like us! So, please don’t think just because this vet they found “prescribes” other medications, that this is a bad preventative. If a client comes in and says a pill is making their dog or cat sick, a more in depth conversation needs to be had as opposed to just saying “well let’s switch.” We need to discover if the medication really IS making the patient sick or if something else is occurring.

This product has FDA approval and has been extensively studied in dogs. If there was an issue, the company WOULD want to figure it out and address it. These companies know that if we vets feel that it is not safe, we will not sell it. We need to use science and research to figure out if a medication really is a problem. We see NO evidence that this medication is harmful. If I hear or see any evidence, I will have no problem calling everyone on the medication and switching them. As of now, we have NO evidence of this.

I have used this medication on my pet and I have worked with many staff members as well as clients that have never had an issue. I feel it is very safe to continue to be given with a FULL MEAL.



  1. I have recently been approached about the trifexis issue by a friend who knew I was using it for my GSD’s. I am a huge animal lover so of course the stories circulating has alarmed me. Most all of the research I have done has all been from 2013. What if any recent stories are circulating? Has the issue become more of a red flag or less of a red flag in year 2014? I am so concerned. I’m using it now, but so worried it might cause my pets heart problems because of the negative comments I’ve read. Please answer me with new updated information please.

    Please & thank you,
    Zane Bennett

    • Thank you for your question. I definitely understand your concern as there is a lot of scary statements out there regarding Trifexis. I can start by saying there is no evidence linking Trifexis to deaths in dogs. The “adverse reactions” reported mainly have to do with vomiting, which we know the product will do on an empty stomach(so we recommend feeding a FULL meal when giving the product). We still recommend Trifexis here and our patients continue to do well on the product. The company investigates any reports for adverse reactions to ensure that the product is not causing issues. If the heart problems you mention have to do with the puppies that died, they believe the inflammation around the heart had to do with an infectious disease, not a toxicity from a product. I know it can be stressful to hear about something that could possibly be doing harm. These companies spend a lot of time to ensure there product is as safe as possible otherwise we as veterinarians wouldn’t prescribe them and they would not be approved by the FDA. I hope this answers your question and helps you to feel more comfortable with this product. Please let me know if you have any additional questions.