Reason #3 to Fire Your Vet: Selling Trifexis

Poison Prevents Heartworm and Risks Life

The comments continue to pour in, across the internet: “I gave Trifexis, I lost my dog.”

Did a whole lot of vets miss the memo that giving pesticides to kill heartworm larvae and fleas and ticks has tremendous potential to also kill dogs? If Trifexis side effects include umm, death, wouldn’t you hope your vet was fully aware of that before prescribing it?

Or even stocking it?

I sure would.

But perhaps the profit potential for Dr. WhiteCoat makes him less likely to hear the distressed calls of people who’ve lost a furry family member to this poisonous chewable.

Like the vaccine machine, when your bottom line is impacted by selling something, it’s easier to keep selling than to look honestly at the consequences of what you sell.

Trifexis Side Effects a Year Later?

Imagine happily giving this wonder drug that Dr. WhiteCoat sold you and seeing no illness in your dogs at all.

What’s all the fuss about? Are these people making this stuff up about seizures and sickness and death?

Here’s an eye opening recent comment that appeared on what’s now my site’s most popular page, bar none (The Great Trifexis Hoax: 6 Ways to Spot the B.S.):

Just to let you know that my dog, who is a year and 7 months this week, was on Trifexis since she was 4 months old without any discernible issue. This past September, she had what I now know was a small seizure … head /throat/ear spasms … in the middle of the night. We called the emergency vet but didn’t end up going as whatever it was, … she went back to sleep. We emailed our regular vet that night and spoke to her the next day but she wasn’t concerned as ours was an isolated, and mild, incident.

This past Friday night (right after Thanksgiving), she had another incident but much more symptomatic of a seizure. I was scared to death and we were in a hotel out of town. We went to the emergency vet who didn’t say much of anything but gave us an article on seizures and tremors, and recommended we see a neurologist as soon as we get home. I had given her Trifexis at 8:15pm right after dinner, and the seizure was at 5:00am.

It wasn’t until we got home last night (Monday) that my other half remembered we had emailed the vet after the first incident, and to our amazement, it was ALSO ON A NIGHT WE HAD GIVE HER TRIFEXIS AFTER DINNER. I was so relieved to have found the connection and be able to tell the neurologist this morning at our appt. Though she was very reluctant to commit to the correlation between Trifexis and the seizures (kinda odd, as it’s not a regular vet but a specialist practice, so they don’t sell it there), she did advise we stop the Trifexis after our dog passed her neuro exam with flying colors. Also, not to put her on Comfortis or another that I can’t recall right now. I think we’re going to go the Heartguard route but would love advice in that area.

Anyway, I’m replying to your post bc Tippy mentioned that you hadn’t seen any effects in a year of your dog being on it, and NEITHER DID WE! I am sick that I was unknowingly poisoning my baby girl, sick that this med is still being prescribed, and concerned that some (most?) vets aren’t doing their due diligence and researching what they recommend. It unfortunately only takes a quick Google search to see what’s happening! I do realize that ultimately, it’s on me to research what I give my pet but why wouldn’t we all trust our vets who, at least in my case, we chose after MUCH research and bad experiences elsewhere.

I’m calling my vet first thing tomorrow and telling our story. This whole situation has me channeling Erin Brokovich!

Whitney, 12.1.2015

Death After a Year’s Use

The Indianapolis Star’s investigative reporter, John Russell interviewed me briefly months before his hard-hitting series came out on the pet drug industry, lead by a story on Trifexis and it’s association with (then) over 700 reported deaths.

His lead animal story is about Sesame, a healthy eight year old Golden Doodle who collapsed and died 5–6 days after a dose of Trifexis. The day before, Sesame had vomited twice and was wobbly. After a rush into the E.R. on the fateful day, Sesame died on the table, with no discernible cause. His liver enzymes were slightly elevated.

Sesame’s owner, Dr. Nimu Surtani, a human surgeon, found no evidence that anything else could have caused Sesame’s death. He was a hale and hearty 65 pound picture of canine health, who regularly ran with his owners. A month prior, he’d been put under for a dental cleaning and sailed through with flying colors. All tests then were normal.

And he died, days after taking Trifexis. After having been on it for nearly a year.

You could not kill a dog quicker,” Surtani recalled, “unless you gave him the wrong medicine and put him to sleep.”

What Is This Stuff?

Trifexis side effects come from the combination of a flea pesticide called spinosad and an heartworm larvae pesticide called milbemycin oxime.

Spinosad, derived from a soil bacteria, started life as a crop pesticide. (That alone should start your inner concern voice: “Would I knowingly consume a pesticide? Heavens no!”)

An Indianapolis Star investigation found that … spinosad, ranks third among all pet drug ingredients for reports of convulsions, fourth for blindness, sixth for aggression and paralysis, and seventh for reports of unconsciousness, according to the latest data available from the U.S. Food and Drug Administration.

The other active ingredient, milbemycin oxime, ranks fifth for convulsions and ninth for deaths.”

Indy Star Article

If you are a label reader (you are, aren’t you?), you may know that spinosad is the active ingredient in the flea poison called Comfortis, made by the same outfit. (Don’t you love that name? Makes a poison sound like a plush dog bed or hammock on the beach).

Like most flea and heartworm poisons, spinosad kills pests by paralyzing their nervous systems. No longer able to respire, they suffocate.

The nervous system. Isn’t that the same system involved in sudden weakness and ataxia, the wobbliness commonly listed among Trifexis side effects?

Milbemycin is classed as a macrolide, and is sold as a stand-alone heartworm drug called Interceptor. It’s a near cousin to ivermectin, the widely used dewormer that used to make me sick every time I used it in horses.

Interestingly, the warnings accompanying Trifexis speak of “serious adverse reactions” when spinosad was combined with ivermectin.

Not too large a leap to imagine similar serious consequences from combining spinosad with ivermectin’s cousin compound in the same family, is it?

Problem? What Problem?

It’s business as usual at Elanco, the veterinary division of Eli Lilly and Co, who is still selling the drug associated with so many illnesses and deaths. They are sticking to their story: there’s no proof. “And we are helping so many, many dogs avoid the horrible risk of heartworm and fleas and ticks.”

It’s as if nothing has happened, in the eyes of Big Pharma in Indiana.

As if all the people experiencing illness and death after using Trifexis don’t exist. Or are the victims of short sightedness and, the bane of scientism advocates, making a correlation into an actual cause.

As Elanco spokewoman Julie Lawless (gotta love her name being part of this story) said,

What we continue to say is there is no link established between Trifexis use and death… Reports are not an indication of cause.”

And the people who’ve experienced illness or worse, death, after giving Trifexis know better.

Detox Time

If you have had animals taking Trifexis who haven’t shown side effects yet, I submit you are in a dangerous position. As you’ve seen, animals have been stricken and even died after no apparent adverse reactions for a year or more on the drug.

I’d advise getting off the risk wagon immediately so you’re not wondering when the other shoe is going to drop, making your dog a statistic.

A good first step when you stop using Trifexis is a deep acting detox protocol. Pesticides are poisons, right? That’s how they kill the pests. They poison their little nervous systems.

Poisons are largely processed in our most amazing of organs, the liver, which, when it’s not busy moving toxins out of the body, is also tasked with:

  • blood building
  • immune system enhancement
  • digestion of fats
  • storage of fat soluble vitamins
  • hormone management
  • blood sugar management

…and innumerable other functions that mammals depend on for health.

Helping your dog’s organs of detoxification helps your dog stay ahead of the risks that chemicals like Trifexis pose.

It’d be worth your while to search out a detox protocol you trust if your animal has been poisoned with Trifexis. Here’s one I use in my homeopathic practice.

What’s the Alternative?

I’m glad you asked.

I knew from early experiences with patients in Hawaii (land of year round mosquitoes!) that preventing heartworm could be accomplished without the tradeoff of intoxication of your pet. It’s been confirmed over the 25 years since, with patients in Texas, Florida, and many other states and countries.

I was moved to write up the protocol that I developed years ago, and further refined that a year back with an audiobook version. Hundreds of you now have seen for yourselves that it works for you, year after year.

It’s called the Drug Free Heartworm Protocol, and it’s presented in my ebook and course called Vital Animals Don’t Get Heartworms! (<–click here for details).

In the book, I walk you, step by step, through what’s worked for hundreds of my patients for over 20 years, most of them living in heartworm endemic areas.

Willful Ignorance? I’m Not Paying for That!

But let’s not mince words, shall we? If your vet is still sending Trifexis out the door of his clinic, and has chosen to ignore the many reports of its side effects that range all the way to death, why would you give him your hard-earned money?

You’ve got a card to play to help change this practice and send a clear message to everyone you share your story with.

Fire Him!

And tell him why.

Then, tell the world.

Are you not sick and tired of risking your animal’s life in the name of prevention?

I thought so.

Tell us in the comments how you’ve dealt with this. Remember: you are not making these decisions for Vital Animals in a vacuum. Many have boldly gone before you. Sharing our stories helps us all grow in confidence.

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  1. Tiffsny on January 18, 2021 at 8:17 pm

    Looking for information on treating lungworm. My lab was diagnosed with lungworm in September and treated with Panacur which didn’t completely rid her of the parasite. On November 6 she was started on Advantage multi as it is known to be a treatment/preventative. Shortly after she started having strange behavior and 26 days later had her first witnessed seizure in the middle of the night. She saw an ER VET the night of the seizure and was allowed to come home after 24 hours and no more seizures. I was given the ok to give her the spot on as it was safe. I had not yet made the connection. I gave her the second dose. Two days later when I got home from work she was wobbling and unsteady. She even stumbled and fell while going to potty. She improved that night. 7 days later I came home to find her and she had apparently had a seizure…she couldn’t walk and her feet were drawn up. Vet prescribed Valium.later that evening she was completely normal. No seizures since and an internal medicine vet said seizures were due to the Moxidectin. The only thing left to treat the lungworm that I know of is Interceptor plus. A neuro vet said this was safe to use. I’m worried of another seizure but know the lungworm has to be treated. Do know anything else that would work or think the interceptor plus is ok?


    • Will Falconer, DVM on January 18, 2021 at 10:28 pm

      Hi Tiffany,

      My best advice would be to seek out a qualified homeopathic vet to treat this dog. One, it’s 100% safe in trained hands and two, it’ll get her susceptibility to ALL worms cured. Merely killing worms with a poison is never going to touch her susceptibility and, as you’ve experienced, “killer” drugs aren’t safe.

      I tell you how to find one on my Recommended Resources page. Scroll down to the AVH list and be sure to watch the video there on how to choose the best one for you (even if none are local to you).

  2. Mieko Coverson on December 9, 2020 at 2:12 am

    Hello Dr. Falconer,

    I lost two dogs in 2018 and this year in March. they were both 13 years old Shih Tzu.
    After reading this article I strongly believe that Trifexis was what caused their deaths. They both started having really bad seizures when I gave the heartworm guard Trifexis. One of my dogs also started to have neuro damage. I didn’t think that the medication was the problem for a long time. After my first dog died, I started suspecting the medication. I gradually then completely stopped giving trifexis to my other dog and the seizures subsided. I do believe it was just too late because after sometime of his seizure free life, he dies of a seizure. They were both very healthy dogs and it breaks my heart that I might have given them something that may have harmed their bodies.

    Now I have a new Maltese puppy. I do not want to give anything to harm my puppy but at the same time I want to prevent heartworm. I know when I go to the vet clinic they will want him on a heartworm guard. So my question is, what is the safest heartworm prevention?

    Thank you.

    • Will Falconer, DVM on December 9, 2020 at 5:28 am

      Well, I’m biased because I’ve had my own drug-free protocol out now for decades that’s been bringing in negative tests from all over the place, including places like Florida where they like to brag about the size of their mosquitoes! You’ll find details here.

  3. Stephanie on November 14, 2020 at 2:17 pm

    My dog was experiencing lack of appetite and seemed a little bit down, the only different thing in his routine was that his doctor prescribed him Trifexis. After reading all the articles on it, I am now scared. Could he die or get a serious illness from one dose? It was his first time ever taking it and I’m not considering doing it ever again seeing how he got. Will he get better?

    • Will Falconer, DVM on November 14, 2020 at 8:03 pm

      I hear your concern and second it, Stephanie. Some have clearly died after this drug, though probably less that those sickened. I’d recommend two measures to minimize the risk, both aimed at detox.
      The first is my homeopathic protocol, linked here (and also at the bottom of the article you’re commenting on).
      The second, our physical product, Vital Animal Detox, which is best given daily.

    • H Marsh on November 13, 2022 at 11:11 am

      Trifexis caused seizures in my perfectly healthy girl. The poor thing is suffering from an attack on her system every 2 weeks. It is heartbreaking to watch. We have tried many different things. Once the damage is done by Trifexis it is impossible to reverse. How can a company responsible for so many adverse reaction & death sentences to dogs be allowed to continue to distribute the poison with no responsibility or consequences?!!! I watch her get closer to death with each seizure. 😿 So sad!

      • H Marshall on March 23, 2023 at 1:56 pm

        My girl also suffered seizures after Trifexis. I am heartbroken to have to watch these seizures twice a month. They started off with short reactions and now they are increasing in length & intensity. How can a company get away with selling a product that leads to the destruction of a beloved pet’s quality of life? Elanco legally should be made to reimburse the owners for wrongful deaths plus pain & suffering of the owners plus vet bill compensation. Most destructive poison on the market!

  4. Carol on July 22, 2020 at 11:18 am

    Our dog Lily is a 7 year old mixed Pit/Whippet. She has been on Trifexis for two years now and only takes the medication 6 months out of the year. Has had issues with not wanting to eat the day after taking Trifexis but seemed fine after that. She hates taking this med. We don’t think she has ever received a “full” dose of this until 10 days ago. My daughter would see bits of the medication in her food bowl every time but was not concerned that Lily did not get a full dose. Well this time she swallowed the entire pill. The next day she did not eat and was lethargic which is new. She seemed to rally a little the day after that and ate a small amount but was not drinking fluids. By the third day she was still lethargic and not eating or wanting to drink. My daughter had to give her liquids by syringe and rubbed some honey on her gums. This perked her up and she was able to eat once that day. During this her eyes were glassy and and she just wanted to sleep. My daughter contacted her vet who told us to continue to give her water by syringe if necessary and gave my daughter some things to monitor for. She did not have any fever, vomiting or diarrhea. She seemed to come out of the lethargy after 5 days and is drinking better but is only eating once a day. She adamantly refused to eat from her dog bowl. She is also refusing her normal dry food. My daughter has gotten her to eat some cooked chicken from a plate and she will eat about 1/2 to 3/4 of a cup per day. My daughter took her to the vet and he said to get a second opinion. He did not test her for anything. He thinks she is having a reaction to the Trifexis (duh). He is a new vet for Lily. My daughter is in the process of changing vet’s because the practice Lily was going to was so large. Lily has an appointment with her regular vet practice tonight and hopefully they will do a full exam including lab work. We are worried sick. This dog is my daughter’s support dog and they live 3 hours away.

  5. Ebony Torrey on May 16, 2020 at 12:32 pm

    My 6mon old puppy has had 2 seizures after taking Trifexis. He had 1 on 5/6/20 and today 5/16/20. My niece did some research this morning and noticed the side effects. I’m a new mommy and trusted my pup to be taking care of but I have failed. The seizures are heartbreaking to watch. I removed him off the meds

    • Will Falconer, DVM on May 18, 2020 at 12:28 am

      Seizures are indeed hard to go through. You feel so helpless, as your pup struggles and loses control for what seems like an eternity. I’ve got two things to help: a homeopathic detox protocol and a powerful physical product we’ve created called Vital Animal Detox. They are complementary and I’d suggest using both. All the best to you, Ebony.

  6. Sarah Allyson Smith on March 25, 2020 at 1:12 pm

    Very interesting read. I have a 4 year old Pitt who was diagnosed with Lymphoma today. We have always used other HW medication, but in June we moved to a new area (new vet)- they recommended Trifexis. We gave it to him December 19. Within weeks of the pill, he was developing strange symptoms- increased thrust and urination. His bloodwork came back that he was hypercalcemic and his lymph nodes were increasing in swelling while we continued testing over the last few months.
    He has never had any previous health concerns. Obviously I have discontinued the use of this medication, but I am on high alarm that I know the cause of this lymphoma. Nothing else has changed- healthy dog, pill, cancerous dog within a month.
    How can there not be a correlation?!

  7. Ashley on January 4, 2020 at 6:25 pm

    I’ve never had issue with trifexis or comfortis,or interceptor plus,not even when accidentally overdosing a couple of dogs.I think people just want an explanation to their dog death and will blame the first convenient source they can think of, I’ve had my entire kennel on trifexis and my cats on comfortis.I’ve used interceptor plus in between.I’ve been doing this for years.No issues what so ever.

  8. Jacqueline on December 19, 2019 at 5:53 am

    I feel like an idiot not knowing any of this but I just gave my 2 year old cavaliers their dose of Trifexis last night! This morning at 5 am they both became incredibly clingy, one more than the other and there is slight shaking going on. No vomiting yet, Is there anything I should do or could we still be safe at this point? I will never ever give them Trifexis again after reading this!

    • Will Falconer, DVM on December 23, 2019 at 3:46 am

      Hi Jacqueline,

      If you scroll back up to the article, towards the end, I mention a detox protocol I use homeopathically to help these guys get over their poisoning more quickly.
      All the best with your two in trouble.

  9. Michelle Lenihan on November 2, 2019 at 3:39 am

    As I lie here on the floor at 4:30am trying to comfort my dog, knowing he won’t be with us much longer, I thought I would add my opinion. My husband and I believe Trifexis has killed our dog. When he was 7, we started him on Trifexis as recommended by one of the vets in the practice we use. The night of his second dose, he had a massive grand mal seizure. We took him to the vet and the first thing this Dr asked was “is he on Trifexis?” Um, red flag anyone? He has had seizures for a year now. Once on the anti-seizure meds he could never come off. A couple of nights ago he had two seizures. He’s never really recovered this time. All of his blood work came back good but, neurologically, not so much. I would say “lowering the threshold for seizure” equates to causing seizure. Trifexis, even in just two doses more than a year ago, killed my dog’s brain. And my heart.

    • Will Falconer, DVM on November 2, 2019 at 10:32 pm

      I’m so sorry you had to go through this with your dog, Michelle. Thank you for sharing this. His demise will hopefully help many others to avoid a similar fate. (And wow: the red flag couldn’t be much clearer, could it?). All the best to you and your husband in dealing with what must be an immense grief. Just know that, at the time, you knew what you knew and acted accordingly. Who wouldn’t trust a vet in a familiar practice when he recommends something to “help” your beloved dog? Please forgive yourself for that misplaced trust. You did your best in the circumstances and are now wiser.

    • vet on January 4, 2020 at 6:29 pm

      If your dog had heart worms then this would make perfect sense that trifexis killed your dog.I’m sure you had your dog tested, but sometimes with test,they will show up negative even when they are really positive.If you find yourself in this type of situation again I would have a necropsy done to determine the cause of death.I’m sorry for your loss.

  10. Questioning on September 1, 2019 at 11:22 pm

    Interesting that you speak of money grubbing Dr WhiteCoat then conveniently offer your alternative for $50-100.

    • Will Falconer, DVM on September 2, 2019 at 12:48 am

      Not sure where you pulled the figure from, but since you don’t even use your name here (and try two different lame aliases FYI), I’ll assume you’re a shill for Big Pharma or a version of Dr. WhiteCoat yourself, who not only marks up vaccines wildly but profits again from the chronic diseases you create in over vaccinating all your patients.

      Shame on you for blowing that kind of smoke here. We can see right through it.

  11. Jolene Hager on July 19, 2019 at 10:19 am

    My 5 month old Aussie began to have seizures this past weekend. $1500.00 later and they still don’t know why (all tests normal). Our vet referred us to a neurologist, Which we haven’t been to yet, because I’m not ready to pay $2500.00 for an MRI. You would think that the vet and the emergency room staff would have maybe told us it could be the Trifexis, but no, I have to hear from my mother in laws neighbor that Trifexis caused seizures for her dog too. Now that I have read this, and the comments I’m in shock and awe that this poison is given by a vet. I’m ashamed I didn’t do research before I gave it to her, Stupid me trusted the vets recommendation.

    • Jolene Hager on July 19, 2019 at 10:21 am

      P.S. Does anyone know if the seizures stop after no longer using Trifexis? I don’t want her to suffer anymore.

      • Will Falconer, DVM on July 20, 2019 at 10:14 pm

        I’m so sorry you’re dealing with this, Jolene. Arrgh. Just FYI, you’re being pushed into expensive diagnostics that, to my knowledge, would have zero practical application. Seizures are 99% of the time deemed “Idiopathic” (i.e. without known cause). I guess there’s a slim possibility that there were some malformation in the brain they could possibly find, but if you saw the correlation with dosing this poison in fairly close time, odds are you’ve got all the diagnosis you need.

        Will the seizures stop simply by stopping the poison? I wish it were that simple and clear, but the converse is most certainly true: if you continue to use this pesticide, neurotoxic as it is, you will most certainly see more.

        I’d start my homeopathic detox ASAP, and if still seizures after that, urge you to get a homeopathic vet hired to help you. Here’s the detox protocol link:

        Wishing you all the best with your youngster and please post us back as this unfolds further.

      • FYI on September 1, 2019 at 11:28 pm

        Trifexis does not “cause” seizures per say in dogs. However in a dog already prone to seizures, it may allow them to be seen more frequently as it lowers the seizure threshold. Hence the reason the manufacturer advises against using it in seizure-prone patients. So no, stopping the medication may not stop the seizures as your pup was prone to get them anyway but stopping it may decrease their frequency.

        • Will Falconer, DVM on September 2, 2019 at 12:44 am

          So, please tell us, FYI: how do we know ahead of time if our animal is “seizure prone?” And, were they born this way? Just dealt a bad hand?

          Or might this idea of being “seizure prone,” like so many others like
          “idiopathic” simply be trying to cover up the fact that these diseases are all man-made?

      • H Marshall on March 23, 2023 at 2:06 pm

        My poor girl is continuing to have seizures. Once they start, they intensify. I hoped that they would stop, but it was wishful thinking. Trifexis destroyed my beautiful, healthy, precious dog. Heartbreaking!

  12. Jeanette on March 9, 2019 at 3:15 pm

    Many thanks for this post! I realize that this is an older Post and that it may not be responded to but I have to try. January 29th 2019 our 28 lb Jack Russell Australian cattle dog mix became ill. Maya started shivering, was lethargic would not touch her food and was disoriented. We took her to the emergency hospital they ran a few tests and found that all of her tests were normal could not find any issues they gave her fluids under the skin and told us to go to the vet the next day for another panel to make sure that she’s all right. we took her to the regular vet the next day and they ran every test under the sun in a full panel blood screen and could not find anything wrong with her. The vet prescribed gabapentin. She did recover after several days. I have no clue what the issue was. On a side note we do administer trifexis on the 15th of every month. So this was several days after that she had issues. Now roll around to February 26th and The same symptoms start to appear. However the difference was that approximately 3 days prior to the 26th she was excessively drinking water. Her dish is about a quart and a half water bowl and she would go through that in a day and it used to take her a couple of days to go through it. Then on the 26th she started the same symptoms the shivering, lethargic, not touching her food and disoriented. We took her to the vet the vet took tests again tested for pancreatitis all came back negative with the exception of having a fever of 102 the doctor prescribed rimadyl. Now my thought is that with a human with all these symptoms they would probably prescribe an antibiotic so I thought the same for a dog but not with Maya they prescribed a medication that is for osteoarthritis?? Did not make sense to me. Maya’s condition worsened and over the next couple of days had to call the vet back and take Maya back in for more tests. Maya started vomiting.when we took her to the vet her temperature was 104 they kept her and administered fluids to her for 2 days and sent her home with antibiotics. Maya could not keep antibiotics down kept throwing them up. I did not know what to do my husband and I looked online for solutions of how we can help her because we were about to lose her and came across bentonite clay and detox for our pets. I took a syringe needle needleles of course and administered the bentonite clay mixed with colloidal silver to her and she threw up afterwards so I administered more and she was able to keep that down. From that point on everyday Maya has been getting better and better with daily doses of the bentonite clay and colloidal silver. it’s been slow but this past week has been great progress and today she is the bouncy girl that we know and love. I cannot help but wonder if the trifexis may have had something to do with this but it is such a delayed reaction if so. Has anyone else experienced these types of symptoms with such a delay after administering the trifexis? Everything that Maya has with the exception of the water intake points to it. We still have no idea what made her so sick. We all know dogs will be dogs and she could have gotten into anything in the backyard but it’s just uncanny that it’s two months in a row now within two weeks of administering trifexis each time.

    • Jared on June 10, 2019 at 6:20 am

      Yes, we seem to be experiencing the same delayed effects in our dog. He has been on Trifexis for over 2 years, but the symptoms have gotten much worse in the last couple of months. We didn’t connect the symptoms to the Trifexis because they seem to get worse a week or two after administering the dose… Our neighbor’s dog had also been on Trifexis for several years when it suddenly passed away without explanation. The prevailing theory was that their dog had gotten into a pesticide somewhere on their property, but now that we are seeing the same symptoms in our dog we can’t help but wonder about the Trifexis. Needless to say we are taking our dog off the meds, but it’s been about ten days since his latest dose and he seems to be getting worse. Going to try the bentonite clay detox you’ve mentioned.

      • CRISSY on August 21, 2019 at 12:16 pm

        Jared how did the detox work? I have a mini schnauzer that has been on Trifexis for about 2 years and about a year ago started with “allergies”. Now that I’m doing more research I’m thinking it’s caused from the Trifexis. I will no longer be giving my dog this and was wondering if a detox would help him get back to normal.

  13. Phyllis on October 15, 2018 at 12:21 am

    Can Trifexis cause nerve damage? My 9 pound little boy suddenly has a nerve on his back that is driving him nuts. When I rub my hand down his back, his skin jumps like a spasm. Then he “attacks” it like it’s itching him to death! He’s been on Trifexis for a couple yrs. And, he just had his first dental cleaning. I ran across this site looking for possibly side effects from Trifexis and/or anesthesia.

  14. Tara Drake Augenstein on September 10, 2018 at 6:43 am

    Good reply Doctor Will!
    And I’m sorry, after spending 600$ at the Emergency veterinary hospital last night and $200 a visit at the vet plus dumping money into the laps of the pharmaceutical companies for years to poison my dogs…. I don’t mind throwing a couple of bucks your way! Oh, and by the way, I’m kind of in a hurry! Hearing that these dogs are expiring so quickly! My Standatd poodle has been reluctantly taking Hartgard from me for the last couple of years and his appetite has suffered he’s occasionally lost his lunch… last night about 45 minutes after the dose he began vomiting and didn’t stop. When he began vomiting blood, stomach lining and mucous and I noticed him having trouble defecating with blood in it as well (diarrhea) we rushed him to the ER hospital at 2am worrying about bloat of all things! They gave him a shot of antinausea Med and an iv bubble after determining that it wasn’t Addison’s disease but he had been poisoned N.C. his liver enzymes were high. I knew it was the HG N.C. of the time frame and previous nausea!
    Now he won’t take Gatorade or water from me. No rice or chicken. It’s only been a day, but HE KNOWS, that I gave him that poison. I hid it in peanut butter and he’s not going to take anything else. He was going to eat his kibble when we got home but I took it away. He’s my service dog. We’re inseparable and I’m devestated! He’s lost his trust in me and he tried to tell me. I need to clean his liver and restore his intestinal flora but don’t know where to start…. B12? I have sublingual, I have milk thistle, Kefir, He won’t take anything hidden in anything. He’s nauseous but won’t even take peppermint. Will it pass or should we go to our regular vet for more cerenia?

    • Will Falconer, DVM on September 10, 2018 at 8:04 am

      Arrgh, Tara, that’s the hardest position to be in and you’re not the first to tell me the “disguising the poison” trick backfiring like this.
      Head over here and get him on a homeopathic detox asap. He doesn’t have to “eat” it, you’ll see.

      And keep us posted please.

      • Tara on September 10, 2018 at 11:54 am

        Thank you, Thank you, thank you! We’re stable for now. I’ve downloaded and purchased this valuable information. I appreciate your quick response. My vet has the number for the ER on the machine … I’ve ordered the easy detox from the local health food store and my DH will pick up on his way in. We’re on our way out of this nightmare! I’m excited to start over!

  15. Amy Stovell on March 6, 2018 at 9:39 am

    If you are trying to release animals from the grips of these drugs, and truly want to help people, why is there a cost for the alternate information? I’m just learning of the effects of Trifexis and Apoquel…

    • Will Falconer, DVM on March 9, 2018 at 3:30 am

      Hey Amy,
      I don’t know about you, but I’ve got bills to pay while I live down here on the planet. By your logic, anyone who wants to help others (truly) should do it for free, am I reading you right? Maybe you’d explain that to my landlord, the utility companies, the grocery store, etc. when they ask why I can no longer pay them. And the professors and tech schools and universities who have information to share that helps people in various ways? Same deal? I’m sorry, but I’m not following your line of thinking. Google is free, last I checked. See how you do sorting all that out.

  16. Charlotte on July 21, 2017 at 8:20 am

    Hello, I’m writing for a friend. She had 3 very healthy and well-cared for adult dogs around 3-5 yrs of age who were given Nexgard on April 3rd. By the end of the month, all 3 dogs had developed deafness as confirmed by 2 separate veterinary exams. It appears the deafness is irreversible. She contacted the pharmaceutical company and they deny any correlation between the drug and the health effects. Are you aware of any similar cases?

    • Will Falconer, DVM on July 22, 2017 at 5:43 pm

      I’m not personally aware of this, Charlotte, but 3 or 3 dogs? Unrelated? That’s pretty wild. I’d google the drug + deafness and see what you find.

  17. Heather on June 3, 2017 at 3:52 pm

    I am very interested to know if there have been any other issues with this drug. I have a 4 tear old lab/pit mix who within a month of being sterilized,vaccinated, and given triphexis ended up with lymphoma. She was a rescue and had never had any issues until then..

  18. Heidi on April 23, 2017 at 8:10 am

    I need help, my dog absolutely hates Trifexis, my husband crushes it up in a can of food and she will go days without eating just to avoid it. I refuse to make her eat it anymore. Which is why I am doing research and came across this page 🙁 I need help with what to give my baby for heartworm, fleas and ticks etc. Would love to go natural, any suggestions. She is a 2 yr old german shepherd 🙂 Please advise.

    • Will Falconer, DVM on April 24, 2017 at 1:00 pm

      Heidi, I’m so glad you’re committed to keeping the poisons out of your dog. I’ve had lots of lots of people having negative tests year over year using my drug free HW prevention protocol. You can read more about it here.

  19. Kim Swaim on April 8, 2017 at 8:40 pm

    How do you suggest treating a heartworm dog?

  20. Susan Wolfe on December 30, 2015 at 7:57 am

    I just want to make your readers aware that there are Facebook groups for three of these products: Does Bravecto Kill Dogs? Does Trifexis Kill Dogs and Does Nexgard Kill Dogs? You can see similar patterns of side effects reported worldwide on these groups.

  21. Cyndi on December 15, 2015 at 4:42 am

    Our dog Kooper was on Trifexis for 8 months. He was a beautiful cocker spaniel and was healthy. I switched to Trifexis bc we had a young child and I didn’t like the chemicals on his back from Revolution. I wish I had known then what I know now. On Easter weekend Kooper stopped eating, so unlike him, and was sleeping all day away from the family. I took him to the vet Monday morning and later that day got the ca that his liver enzymes were elevated. I started giving him food to support his liver and supplements. Within a week he was bloated. Back to the vet where they took a liter of fluid out of his stomach. It was back the next morning. He was in complete liver failure. He died two days after and I have no doubt the Trifexis did this. I’ve reported it to the vet and online. I’m angry bc I made the decision to use that crap on him.
    We have a new dog who is chemical free. My moms new dog is as well. Kooper is missed dearly but he taught us many beautiful lessons.

    • Will Falconer, DVM on December 15, 2015 at 8:22 pm

      Oh, Cyndi, what a tragedy, and from his first dose. Wow, what a cautionary and sad tale.
      Thanks for sharing it here.

  22. Miles on December 14, 2015 at 9:17 pm

    How can we prevent fleas? Nobody is sharing what works & what doesn’t. This is Austin /Cedar Park Texas. Fleas are everywhere!
    We live in a world where everyone wants to make a dollar. But nobody wants to help.

    • Destiny on December 14, 2015 at 11:52 pm

      Bug Off by
      I have used it for years. I normally stop in the winter time where I live, but this year figured out I needed to continue through the winter and no more problems. 🙂

    • Will Falconer, DVM on December 15, 2015 at 8:23 pm

      Hi Miles,
      One of my most popular pages: Non-Toxic Flea (and Tick!) Control. Lots of understanding there for you.

  23. Destiny on December 14, 2015 at 5:35 pm

    I dont give my dogs drugs. Too risky.
    Back in October (in AZ) we had a major tick problem. I pulled about 10-15 off my 8 lb dog. All were very tiny, and while attached, had not filled with any blood yet. I cleaned all the wounds with colloidal silver. So far I havent seen any side effects from the ticks – and we sprayed our yard with Wondercide and they *seem* to be gone! NEVER had a tick issue in the 4 years we lived here 🙁 We believe a stray dog we found brought them on and it has been hell to get rid of them. I am hoping my dogs dont get any tick-borne illness.
    PS. I know you have talked about raw diet, but could you sometime post a “basic menu”? I know a lot of people would like to know your thoughts on this. I of course follow prey model raw and my dogs LOVE It!

  24. Darlene on December 14, 2015 at 5:14 pm

    I let my vet convince me that my two toy poodles needed Revolution. We were going camping and although I should have known better, I wanted to protect my sweet 7 pound friends. The camping trip went sour fast, and if I had not found an amazing holistic vet, I’m not sure the tiny male would have survived. He could barely get out of bed and was having tremors and seizure like episodes. Never, ever again!

    • Will Falconer, DVM on December 14, 2015 at 5:24 pm

      Wow, Darlene. Nothing like a close call to change your mind forever! Do you recall what the treatment was that brought your wee friend back?
      Very glad you had a happy ending.

      • Darlene on December 14, 2015 at 7:04 pm

        Acupuncture, biopuncture, B12 shots, and an assortment of homeopathic remedies for detox, healing and trauma. My dog made a full recovery over the course of a few months although his energy took about a year to return. I recently read your article on dental care and tried raw chicken necks for the first time the other day. They loved them and I hope the tartar will start to disappear. I was a bit hesitant because my girl gulps everything but she did okay with close supervision. It is the only bone I have been able to get them to chew.

  25. Barbara Schermerhorn on December 14, 2015 at 3:45 pm

    Raw, titer, drug free here as well. So grateful for all your Info that will help keep our kids healthy for many years. 2 Pem Corgis.

    • Will Falconer, DVM on December 14, 2015 at 5:08 pm

      Way to go, Barbara. I wish you many, many years of sterling vital health! With what you’re doing, you’re setting the conditions to make that possible.

  26. Alison Tapp on December 14, 2015 at 2:53 pm

    Never had a problem with Triflexis because I’ve never used it. Had a very poorly girl after giving her Advantix 5 years ago. Now all raw fed and chemical free. 6 dogs

    • Will Falconer, DVM on December 14, 2015 at 4:59 pm

      Nice, Alison. Great lessons can come from experiences like yours. You saw clearly what happened, changed course for your animals, and everyone has benefitted.

  27. Lila Hlebichuk on December 14, 2015 at 1:04 pm

    Many years ago I took my one year old Collie in for a heartworm test. That is the test not treatment. I have never given heartworm medication to my dogs. They took her in the back room without me and a few minutes later brought her back and said when they expected to get the results. Oh by the way, they told me they also gave her the 6-month heartworm injection. This was without consulting me and without getting the results of the test. Collies are so sensitive to these toxins, however she did not get ill. Her test came back negative. I do feel that although subtle she never had the vibrant health of her litter sister that I had also kept from this litter. She died a couple of weeks after her 12th birthday. Her litter sister lived another year and a half. Lila

    • Will Falconer, DVM on December 14, 2015 at 5:04 pm

      Wow, Lila, she must have been a very healthy specimen to withstand that injection. That’s ProHeart 6, folks, banned from the market because of many deaths, but it’s back in the last couple of years.
      Another caution Lila is sharing here: never let your dog be “taken to the back” on a vet visit. I’ve heard of similar horror stories of multiple vaccinations, antibiotics, etc. all given w/o the owner’s permission.

  28. Darci Michaels on December 14, 2015 at 1:03 pm

    Just finished the 5th summer of no heart worm drugs. I follow your protocol Dr. Will. We (dogs) are all heart worm free and healthy.

    • Roger Biduk on December 14, 2015 at 1:24 pm

      Way to go Darci…

    • Will Falconer, DVM on December 14, 2015 at 5:01 pm

      Great, Darci. No drugs and no heartworm either. Best of all worlds. Glad the protocol has helped you.

  29. Peter on December 14, 2015 at 12:58 pm

    Nice article Dr Falconer! I have stopped using Advantix for a while and have been using Tickless bug repellent spray. I just recently stopped giving the HeartGard, it’s the first month I haven’t given it to her. I was told I don’t need it when it’s cold, unless the temp is above 67 degrees, and that when the spring comes, to revisit my options. But I already feed a raw diet, give lots of exercise, keep stress levels low, stopped chemical flea/tick products and reduced household chemical products such as cleaners for bowls and beds. I really hope she doesn’t get worms. I have given her a couple teaspoons of raw organic crushed up pumpkin seeds in her food here and there which i read is a natural dewormer. also stopping vaccines and doing titers. thank you!!

    • Roger Biduk on December 14, 2015 at 1:55 pm

      Hello Peter,
      The best natural dewormer, which is also great for humans, is Diatomaceous Earth [DE]
      Here’s a few links of info you can take a look at:
      • Video
      And I wouldn’t waste good $$$$ on titers… one-time shots are good for life immunity.
      If you do insist on titers, remember that the cost to the vet is now $10-$20 / test with in-house VacciCheck with accurate results ready in 21 minutes
      Several FB friends have told me that their vet has tried to severely rip them off, saying titers would cost $350 / test!

      • Destiny on December 14, 2015 at 5:30 pm

        Some vets wont allow Vaccicheck, or make you buy all 12 and they must all be used in 12 months 🙁 does titers at a low cost. 🙂

      • Mary Traverse on December 15, 2015 at 7:04 am

        I include DE with my horses’s and dog’s food for about a month, a couple times a year. Hey, I also put it in my coffee then too!. Easy to remember— everyone gets wormed! The only trick is to be sure to dampen the mix if the food is dry (like the horses’) so no one breathes those pointy little diatoms!

      • Angela on May 28, 2019 at 4:08 pm

        Hi. I’m highly allergic to fleas. Once bitten they itch for weeks. I had a house guest once that brought her dog and cat and gave us cat fleas for thought we would never get rid of. I tried DE and all it did was make a mess! My dog died from Trifexis. So what is a good alternative that works?

    • Will Falconer, DVM on December 14, 2015 at 5:30 pm

      You’re heading in a good direction, Peter. I appreciate your efforts on behalf of your charge.
      And while the pumpkin seeds won’t hurt (and add some nice zinc and protein and fiber) they are known for working in the gut, not the heart.
      To tell you the truth, I just never worry about intestinal parasites in animals raised like yours. The health and vitality achieved allows parasites no quarter. Even pups who bring some into their early life from mom — the worms disappear within a couple weeks of being on a raw, balanced diet in my experience.
      Carry on. You’re solidly on the Natural Path! No fear!

  30. Karen Henderson on December 14, 2015 at 11:54 am

    Our sweet baby Nevah was killed by this drug. Let me tell you a little about her… She was a bottle baby, her mother didn’t produce the milk she needed. She was also handicapped, she had a fused elbow, but trust me that did not stop her. She spent 99% of her 3 yrs of life in the lap of my Husband. She didn’t get in the floor and play with the other dogs.. The only thing she would eat was dog food. She would not touch human food at all. The only time she went outside was to potty. She slept in a pack and play in our room. She was current on all shots and was in perfect health. We started giving her Trifexis when she was 6 months old. We didn’t see any problems. She is now 3 yrs. old. We gave her the dose of this stuff as we always did right along with the other dogs. 4 days after she woke me up by barking as she had never done, when I got out of bed I walked to her, she was having a seizer. I got dressed and took her right then to the vet. On the way there with my friend holding her she had another seizer. It took me about 10 minutes to get to the vets office, while signing her in and filling out her paper work, she had another seizer, so they took her on to the back. The Dr. came and put me and my friend in a room and said to us that it was a toxicity, she said that she would run tests and cultures to see what was going on. ALL of those tests came back normal. Her blood was fine, all of her organs were functioning as they should, there were no physical signs of why she was, disoriented, not able to stand, she couldn’t even hold her head up. All of this happened overnight. She stayed at the vets office over night, so they could treat and try to flush toxins from her body. the vet called the next day and said that she had a rough night but she could possibly go home at about 2pm. We went to visit with her at about 11am, she was drowsy from the meds, she seemed ok. I called to see if we were still to pick her up at 2pm, the vet then told me that she had more seizers back to back and started convulsing and they couldn’t bring her out of it and she passed at 1:30 that day. The vet had run more tests after and still no signs of any other reason for her death but the Trifexis. She wants me to inform her of any class action suits that may come up because, she had just had another dog come in, in the same condition as our baby… R.I.P our Sugarbaby Nevah…

    • Will Falconer, DVM on December 14, 2015 at 4:51 pm

      Truly a sad story, Karen. I get the sense that, like Sesame in this article, the toxic load kills before the liver enzymes or kidney values have a chance to show something is amiss.
      It would seem this combo of spinosad and milbemycin is above average on the toxicity scale, and yet leaves the victims with little physical evidence of what killed them.
      I wish you all the best. You’ll surely make different decisions now for all the other dogs who come into your care, and we have Nevah to thank for that.

  31. Becky Garcia on December 14, 2015 at 10:45 am

    Thanks for this Dr. Will! Do you see the same problems with Comfortis? I cannot remember which one we tried with our dogs when we had a terrible flea infestation and all my cedar spray/nemotodes/ bathing, washing wasn’t beating it but I gave it to everyone. They all seemed fine but I swear that our small dog developed some ear issues and a month later she was stone deaf. She had not had problems with hearing before but she was sensitive to the topical flea drops and I had stopped using them on her. I always wondered if there was any correlation. I haven’t given it to them since.

    • Roger Biduk on December 14, 2015 at 12:50 pm

      Hello Becky,
      The active ingredient in Comfortis is spinosad which is a neurotoxic, carcinogenic pesticide also found in Tifexis.
      ALL flea / heartworm chemical pesticides on the market are neurotoxic, carcinogenic PESTICIDES…
      If they’re not safe to feed them to children, why would anyone give them to their pets… and you just have to read the warning labels on the box in case of human contact with these dangerous poisons to see what they’re all about.

    • Will Falconer, DVM on December 14, 2015 at 4:44 pm

      Hey Becky,
      Roger beat me to the punch. Although I’ve not seen this level of death and suffering with other products, they are all ultimately built upon a foundation of “unavoidably unsafe,” by the very nature of their use of pesticides.
      Interesting about your little dog’s deafness a month in. Makes you wonder, doesn’t it?

  32. Roger Biduk on December 14, 2015 at 10:27 am

    Greetings Drs. Falconer & Blanco,
    Another great article as usual.
    However, IMHO it would be much better [it’s not too late] to change the title to “Reason #3 to Fire Your Vet: Selling Trifexis or any Flea / Heartworm Pesticdes”!
    Pet parents who are not in the know will think that switching to another poison pesticide, as Whitney does “I think we’re going to go the Heartguard (sic) route” is the safe, right thing to do and we know it’s certainly definitely not!
    How were pet parents EVER led to believe by BigPharmaMafia and unethical / unknowlegeable veterinarians that giving their pets neurotoxic, carcinogenic poisonous chemical pesticides for heartworm / fleas / worms in the form of pills, topical applications, collars or injections whose active ingredients are sensitizers and irritants that cause seizures, terminal cancer, terminal auto-immune disease, terminal neurological disorders, reproductive and birth defects and terminal liver and kidney disease in people and animals which may include ProHeart 6, Revolution, Bayer Advantage, Bayer Advantage II, Bayer K9 Advantix II, Hartz UltraGuard Pro, Hartz UltraGuard Plus, Hartz First Defense, Bravecto, Bayer Seresto, Interceptor, Heartgard, Parastar, Parastar Plus, Pentagon, Parastar, Parastar Plus, Heartgard Plus; Tri-Heart Plus, Vectra 3D, Capstar, Sentinel, Frontline, Safe-Guard, Trifexis, NexGard, Comfortis, Zodiac, Prowormer, Nemex 2, Droncit, Drontal Plus, Roger Biduk – FDA Approved Poison ScullPanacur, Heartgard Chewables, Iverhart Plus, Iverhart, Zimectrin or Advantage Multi among others is the safe and right thing to do…?

    • Will Falconer, DVM on December 14, 2015 at 4:41 pm

      Good point, of course, Roger. I chose Trifexis merely because it’s so painfully obvious that’s it causing serious disease and death.
      For a vet to still carry it after all the horrible press it’s gotten is just a glaring red flag: this vet is willfully ignoring a groundswell of real people reporting real suffering and even death. That’s unconscionable and he should not receive your business.
      Readers: you know where I stand on all these poisons. I’ve written about this prominently throughout the site, so if you’ve missed it, please search on “heartworm,” “flea” and “pesticide” in that lovely little search box, upper right.
      And, as Roger so ably points out, set your bar higher than just another brand of pesticide. You can do so much better on behalf of your animals.

      • Janie Lerner on December 15, 2015 at 8:11 am

        Hi Doc-
        I am a huge fan of yours. I have been warning readers from my website about tick & flea pesticides. When my adopted Chinese Crested mix had a seizure within minutes of applying an on-spot treatment it catapulted me to read about it from decent sources (i.e., you and others). There are natural alternatives to pesticides that are very effective. Yes… pesticides – the EPA defines the active chemicals as pesticides.
        As I dug around I discovered more and more unethical practices within the conventional veterinary community, let alone the rest of the pet industry.
        I can’t thank you enough for enlightening us!

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