Trifexis side effects

Pet owners are reporting the following as side effects of Trifexis: seizures, shaking, lethargy, falling asleep while sitting up, no appetite, no energy and more.

Symptoms may present within hours of taking the pills while others experience side effects after several doses.

My personal clients have seen shaking, lethargy, possible seizure and aggression. Yes, one of the ingredients in this pills IS linked to aggression!

Intervention for Trifexis:

Some pet owners have reported their vet did blood work and administered fluids. Others decided to try a natural supplement to detox their dogs liver by using a Liver cleanse supplement.*Your dog’s weight plays a role in the proper dosage. For example, My vet said my dog (approx. 75 lbs) can have half the dosage I would take. I do this twice a year with him for general maintenance.

If you prefer a liver detox, liquid version, this one has many beneficial ingredients.

Although I am for the natural approach, you must decide what is best for your pet based on their symptoms and the severity of their symptoms. Report reactions: If you suspect your pet has suffered from adverse reactions, you may report it to FDA at 1-800-FDA-VETS or visit their website to file your complaint.

Going forward there are a few things you can do to reduce risk factors.

Access your dog’s lifestyle

A few factors may help you in making a decision of how to proceed in regards to heartworm.

  • Heartworm lifecycle
  • Reported cases of heartworm in your area
  • Preventatives: Alternatives & conventional

Heartworm preventatives vs. treatment

Keep in mind the more things the medicine treats (fleas, heartworm and parasites) the more chemicals we are introducing into our pets system.

For natural flea preventatives, this shampoo can be used instead of using topical treatments aka spot on’s. Here is a spray to use inside your homeand dog skin spray to use for bites, cuts or hotspots.

I should mention one person reported their pet tested heartworm positive while being on Trifexis.

I know of one holistic vet who treated a dog successfully with a black walnut tincture. The dog was tested several times over a few years and it never came back heartworm positive again.


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Disclaimer: The information contained in this web site is provided for general informational purposes only. It is not intended to diagnose or treat your pet. If your pet has a medical problem, please seek medical attention from your veterinarian. Happy Trails & Wag’n Tails will do our best to ensure that information presented is accurate and up-to-date. Happy Trails & Wag’n Tails does not accept any responsibility for damages, loss or illness which may arise in connection with the use of the information published on this website. The decision to use, or not to use, any information is the sole responsibility of the reader. Opinions expressed here are those of individual contributors. © Happy Trails & Wag’n Tails, 2006-2018. All Rights Reserved.

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25 Responses to “Trifexis side effects, reduce symptoms & alternatives”


    I will never give my dog triflexis again. She’s so sick costing us 100.00,s of dollars at vet trying to get her well. I’m so upset.

  2. Emilee says:

    I just recently got a lab, spaniel, terrier puppy who is now 10 weeks old. At his first vet appointment, he was just 8 weeks and 10.6 pounds, they gave us a dose of Trifexis. One week later, Murphy had 3 seizures in one day. SO scary! We took him in and all tests came back clear… heart, blood, liver. They now have him on a seizure medication. We go to a neurologist next week… Could these episodes be from Trifexis!?! Should I do a detox on him?? Please help! He’s such a young sweet little pup. He definitely seems to be more aggressove after taking it as well 🙁

    • Happy Trails & Wag'n Tails says:

      Yes it could and the detox could be helpful. Some Other factors that contribute to neurological issues are mold and heavy metals. If you read my lead free pet food bowls blog, that will give you some more information to consider in regards to things that your pet is using and exposed to every day.

  3. Willie F Jackson says:

    I used Trifexis on my 2 yorkies that have always got alone. After using the product they have gotten very aggresive torwards each on the 2nd day. The 1st day they were very slump and laid back, wouldn’t jump, play, walk or bark, and wouldn’t even eat. Will never use this product again.

  4. Leia Crowe says:

    My dog is 2 and she’s a 55lb staff. Never had a problem with trifexus except the last 2 times I’ve given it to her, hours later she starts to shake and tremble and fall asleep sitting up. This lasts for about 8hrs then she’s fine. I’m going to stop her trifexus and find soemthing else. But 10 days now after her last dose she woke up limping and acting lethargic. She’s at the vet now getting tests done. The vets all claim they’ve never heard of trifexus hurting dogs. I don’t know what else to put her on now, in afraid of this happening again

  5. Pat King says:

    I gave my Aussie Triflexis and she has developed skin rash, scabs what can I do for her

    • Happy Trails & Wag'n Tails says:

      I would start with the liver cleanse / detox to get it out of your dogs system and use the spray listed here to soothe the rash.

  6. Sylvia &Denny says:

    My vet recommended Trifexis for my goldador several years ago and he started having seizures. Once I realized what was causing the seizures it is listed as one of the side effects in the precautions I took him off of it and begged everyone else who was using it to please change meds. My dog stopped having seizures and is now a certified therapy dog visiting nursing homes, hospitals and schools and making many people smile. Thank goodness we caught it in time or it may have killed this wonderful dog.

    • Happy Trails & Wag'n Tails says:

      I’m so glad your dog is no longer on Trifexis or having seizures! That is a wonderful gift you are giving everyone by sharing your dog with them. P.S. Soon I will be sharing some new information on pet health, one of which will include seizures. To stay up to date, follow me on my Facebook or Instagram.

    • Leia Crowe says:

      My dog has started shaking after I give her trifexus… I’m taking her off it. What did you switch to?

      • Happy Trails & Wag'n Tails says:

        Leia, My dog was on a supplement and food regime as described in my cancer and lipoma blogs. I did not have him in a preventative medication. I also followed the guidance of this holistic vet. <--- He is having a sale right now! Fyi: Recently I watched a documentary and other vets said they followed the same procedure, as the above vet, for their own dogs.

      • Rene Johnson says:

        What did you do for the tremors?

  7. B Wright says:

    I wish I had know about the detox sooner, our Lab became so aggressive we had to put him down. He attacked me and my husband, It was devastating. He was almost 3 yrs old and we had him since he was a puppy, spoiled he went everywhere with us. The vet told us it had nothing to do with the Trifexis. the should be sued for still having this on the market!

    • Tammy Huffaker says:

      I have a 16 month old Chocolate Lab & she has had 2 doses of Trifexis & is not doing well!!! She is whining & crying, biting at her back, itching, lethargic, not eating well, disoriented, excessive salivating, panting, fever, trembling etc… what can I do to get this poison out??? PLEASE HELP

  8. Shelby says:

    I gave all 3 of our Argentine Dogos a dose of Trifexis yesterday. The 6 month old pup and the 2 year old dad seem to be doing okay with no side effects. Abby, our mama dog who is just over 2 on the other had is suffering from lethargy. She falls asleep while sitting up, she looks dazed and confused most of the time and refuses to put weight on her hind legs. I am so upset that I didn’t research (which I ALWAYS do) on this drug before giving this to Abby. I am so worried she will die and I’m search frantically for some kind of detox. Why is this still on the market if it’s deadly and why don’t our vets know better?

  9. jessica says:

    dosed my frenchie with trifexis today and several hours later she became aggressive and bit me. she already has some food aggression issues and has bitten us 3 times and I am not 100% but I think the previous 2 issues have been the day of or around the trifexis dosing.

    Anybody else have any experience with this? I am going to be contacting the company and all the blogs etc I can hit in order to get this out there.

    Am I blaming the trifexis for the bites? Possibly so.
    The resource guarding and aggression is a long standing issue we have been dealing with, and I had her off the tri for several months and had very minimal resource guarding issues………

  10. Lynn says:

    This Trifexis is horrible! I dosed my 62lb Boxer..within hours, she was so lethargic she couldn’t keep her eyes open. I feel horribly guilty for not doing the research after my vet recommended it. I’ve ordered the liver detox and will NEVER use Trifexis again. Why my Vet didn’t express any concerns with this product puzzles me.

  11. Susan Williams says:

    My shihtzu has been having seizures through which he howls as though in excrutiating pain. His whole body collapses in the floor as his head and back are in an impossible appearing arch. During this time his bowels and bladder are released. Shortly after, his rigidness relaxes and he lays inert. When he attempts to roll into an upright position, it takes several attempts. On 3/20/15 he had 3 in a 10 hour period in the afternoon to early morning of the next day.

  12. Lilly says:

    I am very worried about my Boxer, We gave her Trifexis Tablet and she is not eating very lethargic

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