Is Trifexis safe? Are the internet rumors of Trifexis side effects true?

veterinary news

Trifexis Side Effects

Added December 2012: This article has collected a LOT of comments from people concerned about Trifexis side effects. I am torn on how to report on this issue. The fact that hundreds of you feel that Trifexis has been harmful to your pet is disturbing. However, if Trifexis is causing these serious side effects then I should be able to find a lot of discussion about this on places like Veterinary Information Network where tens of thousands of vets talk about their cases, and I am not.

If your pet has suffered Trifexis side effects then PLEASE have your veterinarian file a report with the FDA.  If there is a problem with the medication the only way the FDA will act is if they get enough reports of Trifexis side effects from veterinarians.

Original article starts here:

Trifexis is a relatively new heartworm and flea medication.  I have been prescribing a lot of it this year and it seems to be quite effective.  But recently I have heard a number of people on the internet complaining of possible serious Trifexis side effects.  So, is it true? Does Trifexis have serious side effects? Is Trifexis safe?

Is Trifexis safe?What is Trifexis?

Trifexis is a combination of two main ingredients.  The first is something called Spinosad which is the same flea killing medication found in Comfortis.  The second is called milbemycin.  Milbemycin is the same ingredient in Interceptor and Sentinel that is excellent for heartworm prevention and intestinal parasite control (hookworms, whipworms and roundworms.)

This year, Interceptor and Sentinel are not available because of a widespread shortage.  What this means is that many people who want to use an oral heartworm and flea preventative are turning to Trifexis.

The medication is given once a month along with a full meal.

Is Trifexis dangerous?

The following message is rapidly spreading via email and Facebook:

Fwd: hey…whatever you do…DON’T GIVE YOUR DOGS TRIFEXIS. HEARTWORM MED…jack is in the hospital..we tried trifexis for the first time yesterday (his interceptor has been off the market). and by 8 pm symptoms started…I had to take him in at 7 am..lethargy..confusion..tremors with a twitch every 15 appetite..he looks like he’s on an acid trip..his gut is drawn up…all symptomatic of called company …they admit some problems..will pay for blood panels on internal organs for toxicity reports but won’t pay for rest of treatment…so many people will be trying this drug due to not being able to get the discontinued interceptor or sentinel…tell all your dog friends… NO TRIFEXIS…EVER !

That’s a little scary, isn’t it?  But is it true?

Let’s look first at the information available on the Trifexis website in regards to Trifexis side effects:

Trifexis has been demonstrated to be safe in pure and mixed breeds of healthy dogs when used according to label directions for dogs and puppies 8 weeks of age and older and five pounds of body weight or greater. You should discuss the use of Trifexis with your veterinarian prior to use if your dog has a history of epilepsy (seizures). Puppies less than 14 weeks of age may experience a higher rate of vomiting.

Important point: Trifexis should not be used in an animal that has a history of seizures.  

Why is this? The makers of Trifexis don’t actually know if the drug is more likely to cause a seizure in an animal.  However, one of their test subjects did reportedly have a seizure shortly after taking Trifexis and so this must be listed on the label as a potential Trifexis side effect.  So far, in my practice, I have yet to have an animal have a problem with Trifexis (or Comfortis which also has spinosad in it) causing a seizure.

It is important to note that if an animal did have a seizure because of Trifexis, it would be most likely to happen within 1-3 days of administration.  If an animal has a seizure later on in the month it would be hard to blame Trifexis for it.

Some more information on side effects, from the Trifexis website:

Like all medications, sometimes side effects may occur. In some cases, dogs vomited after receiving Trifexis. If vomiting occurs within an hour of administration, redose with another full dose. During field studies, no severe or prolonged vomiting occurred. Additional adverse reactions observed in the clinical studies were itching, decreased activity, diarrhea, inflammation of the skin, redness of the skin, decreased appetite and redness of the ear. All reactions were regarded as mild

Well that sounds a little scary, doesn’t it?  But really, if you look at the list of side effects for almost any drug you will see that there is a great list of possible mild side effects.  What is listed here does not seem much worse than the possible side effect list for most other pet drugs.

The truth about Trifexis side effects?

Well, at this point, the truth is that we really don’t know if Trifexis is safe or dangerous.  As with any drug, there will be some animals that don’t tolerate it as well as others.  Is it dangerous enough that it is killing dogs and causing severe seizures?  I would guess, no.  But then, this is why I have written this article.  I would like your help in spreading the word and encouraging people to  leave a comment.  (We did a similar thing when people were complaining about side effects in regards to Kirkland dog food, and sure enough, shortly after I wrote that post and you guys responded with your experiences, a recall was announced!)

Remember, just because you read something on the internet, it doesn’t mean that it is true.  But, if enough people are saying the same thing then there may be some truth.  My goal is to take the information gathered from the comments in this post and put the data together to see if we can see any patterns.  If there is a problem, then something should be done.  If there is no problem, then Trifexis should not be given a bad name.

Have you been affected by Trifexis side effects?

Do you believe that your dog has suffered Trifexis side effects?  If so, please leave a comment below.  It would be helpful if you could include the following information:

  • Your dog’s breed and age.
  • What Trifexis side effects are you seeing?
  • How long after giving Trifexis did you see the side effects?

Thank you!  And please share this information with others so that we can determine the truth!

Dr. Marie.

Related: Trifexis overdose? My dog ate 4 tablets of Trifexis. Trifexis side effects.

If you feel that your dog has been adversely affected by Trifexis side effects, please have your veterinarian contact the FDA and file a report.  You can also either contact Elanco Animal Health at 1-888-545-5973, or report the problem to the FDA at 1-888-FDA-VETS or AnimalVeterinary/ SafetyHealth/ ReportaProblem/ ucm055305.htm    Trifexis side effects can possibly be serious but we are not certain if most of the Trifexis side effects reported in the comments are actually Trifexis side effects or perhaps something other than Trifexis side effects.




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Dr. Marie

Dr. Marie is a veterinarian treating dogs, cats, and pocket pets. Click here to ask Dr. Marie a question.

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803 Responses to "Is Trifexis safe? Are the internet rumors of Trifexis side effects true?"

  1. John says:

    I have a 3 yr old yellow lab named Carly. A rescue who had to go thru heartworm treatment before I could adopt her. I put her on Comfortis with heartgard plus when i found a flea on her. i liked the fact that I could use the Comfortis only during flea season. I did not like the fact that I was having her ingest a pesticide. She vomited on her second dose but otherwise, during the next 4 months she seemed fine. Always gave with a meal. This year the vet recommended Trifexis. Since it was Spinosad like Comfortis I thought all would be OK. Not sure I liked the 12 months of Spinosad AND since she gained a few lbs. (went from 58 to 62 ) her dosage of Spinosad doubled, and the heartworm med is different. Unsure exactly which it is, but I dosed her two months. Each time she was listless and ate less for about 72 hours. Took care of the fleas, though. Bottom line: got my money back on the remaining 4 doses and purchased Heartgard Plus and Frontline Plus. Why? If it makes my dog feel crappy for a few days it probably isn’t good for her and I’ll go with a topical.

    1. Anna says:

      My Standard Schnauzer, Zipper, is having issues standing and supporting his back end. His legs collapse underneath him when he walks. He had minor symptoms with his back end that progressively worsened. He is also having loose stools. His symptoms started started when he started taking Trifexis. I am having detox treatment done by my homeopathic vet. Will this side effect be permanent? I feel like I’ve poisoned my dog.

      1. DrMarie says:

        If this is an ongoing problem I would be much more worried about a possible spinal problem than a problem with Trifexis. Has Zipper been evaluated for possible IVDD?

        1. Debbie says:

          We started giving our dogs which are a 2-1/2 yr old Australian Shepherd, a 9-yr old border collie and a 1-1/2 yr old Havanese Trifexis a couple of months ago. We noticed no side effects whatsoever until time for the 2nd dose. I’m not really thinking these are side effects from the Trifexis though since all 3 dogs did fine @ first. Now only our Australian Shepherd is having problems with his hair falling out & getting flaky skin & bald spots. I’m just wondering if anybody else has experienced these same types of things with Trifexis. The only other thing we did different was give him a bath in Hartz whitening shampoo. I’m leaning more towards his skin & coat issues pertaining to this shampoo. I would appreciate any feedback on either one of these products causing the skin & coat issues.

          1. janet says:

            hartz made my puppy’s hair fall out too.

          2. Maggie says:

            Debbie , I have read that collies should not have the trifecious ( not sure I spelled correctly ) google it with collie in the search . I came across a few articles on it trying to see if it would be safe for my Maltese …I have decided to not use it after reading post by pet owners . It could have accumulative effect also on your collie so second dose may cause more harm than the first and there is some biological marker in collies that makes it especially bad for them. I read it in comments on a poodle rescue site . Good luck

          3. DrMarie says:

            Collies are not more sensitive to Trifexis than other dogs. Trifexis does contain milbemycin, which at a high enough dose could affecte a Collie, but the dose in Trifexis is extremely small. Here is more information:

          4. Jeanine says:

            I gave my mixed breed 6 year old dog Trifexis and had similar problems. She was disoriented and lacked appetite after the first dose. After the second dose, she was staggering around the patio and couldn’t seem to focus. Shortly after, she began losing her hair and became scaly and smelly. We went back to Heartguard after that. It has been three months since that second dose and she still has significant scaly patches on her ears, rear, and tail. It seems as if the treatment has worked its way down her body and to her extremities. She normally has an abundance of hair, similar to a St. Bernard. At this time, the hair on her chest and stomach is so sparse that you can see her spotted skin and one part of her tail is completely bald. Trifexis is the only thing in her life that was changed so I definitely blame it for her problems. We have another dog that did not take Trifexis and he has none of her symptoms, so we know that it is not a mite or other parasitic skin disorder.

          5. Christalina says:

            Yes….the same thing happened to my black lab. His skin was filled with irritation, bald spots. He was loosing hair faster than ever and he didn’t eat much. I have since taken him off Trifexis and wondering if I should just go back to heart guard and topical flea and tick. I feel like his system is finally back to normal and it been at least 3 months since the last does of trifexis

          6. Jane Fredericks says:

            We have an eight year old sheltiie who has been having undiagnosed problems of patches of flaky skin where the hair falls out in patches and the skin is irritated. We have been to two vets, had her on antibiotics for approx. 3 weeks with no improvements, also a spray medication, no improvement. So glad we read this site and feel that Trifexis could very well be the problem, we will definitely stop using it and hopefully the skin/hair loss problems will get better!

          7. Marcia says:

            My two goldens were given this used to use sentinel and that other one that was discontinued. So vet gave me this. They have horrible dry flaky skin and hairloss scary my beautiful goldens

          8. Becky says:

            I just gave my 15 month old Aussie her Trifexis and about 1 hr later she threw up. She has been on Trifexis for about 7 months, but last month the same thing happened. So now I believe that Trifexis is making my poor dog sick as soon as she takes it. She is very tired now also. Now I have to decide what to give her!

          9. Donna Sonne says:

            I have a four year old Spanish Water Dog that is 55 lbs. I have given him Trifexis for the past two months. He has several bald spots, his hair has fallen out in areas and the rest of his hair is growing very slowly. His skin and hair have darkened in spots across his back. Our vet is taking the medication back and we will go back to Frontline & Heartguard. I wonder how long it will take for his coat to be back to normal.

          10. Penny says:

            My Australian Shepherd is about 6 years old and isn’t feeling well from the Trifexis. I gave it to him yesterday with his supper. He is very blah. Didn’t want to go on his walk in the field. He is groggy and of course the vet is closed for the weekend.

          11. tammy says:

            I gave my English bulldog trifexis for three months the hair started falling out in-between her should and neck. I thought it was just her collar rubbing because I kept it pretty lose. Then her hair began for fall out of her chest. She also began shedding really really bad. The shedding has never been this bad. Lucy also doesn’t act as perky as usual either. My advice is to take your dog off the trifexis and try something different. Lucy’s’ hair just doesn’t seem to want to stop shedding. Good luck.

          12. Lacey says:

            I have a three year old boxer APBT mix named Belle. I rescued her six months ago. I have all of her prior vet records and she was always a healthy well maintained dog. i found a flea on Belle one day and decided it was time to get something. I bought Sentry brand topical. She was deathly sick. my hyperactive dog wouldn’t eat, drink, or get off the couch. she had such bad diarrhea that she would leave a trail as she would try to make it to the door to go outside. I washed her with Dawn in the tub once i realized what was happening. She still had fleas. They itched her so badly she shook her ears to the point of giving herself a hematoma. When i took her to the vet they suggested Trifexis. When we got home I administered the pill. no problems. She was till itching like crazy so i bathed her. I use Richards Organics. Sometimes i will use Avoderm. I am always sure to use tepid water and remove all soap residue. I also change and wash her bedding at the same time. I gave her the Trifexix two weeks ago and she is itchier than ever, like so itchy i cant even reach my hand out to touch her, as the thought makes her start scratching. its all she does, scratch and chew. She scratched herself bloody in the night last night which is what led me here. she is also now missing the hair on her thighs and buttocks. its thinned everywhere else as well that i can see her scaly red skin. she has little bumps everywhere like big hives. Poor girl is miserable. she was better off with the darn fleas.

          13. Lacey says:

            I have a three year old boxer APBT mix named Belle. I rescued her six months ago. I have all of her prior vet records and she was always a healthy well maintained dog. i found a flea on Belle one day and decided it was time to get something. I bought Sentry brand topical. She was deathly sick. my hyperactive dog wouldn’t eat, drink, or get off the couch. she had such bad diarrhea that she would leave a trail as she would try to make it to the door to go outside. I washed her with Dawn in the tub once i realized what was happening. She still had fleas. They itched her so badly she shook her ears to the point of giving herself a hematoma. When i took her to the vet they suggested Trifexis. When we got home I administered the pill. no problems. She was still itching like crazy so i bathed her. I use Richards Organics. Sometimes i will use Avoderm. I am always sure to use tepid water and remove all soap residue. I also change and wash her bedding at the same time. I gave her the Trifexix two weeks ago and she is itchier than ever, like so itchy i cant even reach my hand out to touch her, as the thought makes her start scratching. its all she does, scratch and chew. She scratched herself bloody in the night last night which is what led me here. she is also now missing the hair on her thighs and buttocks. its thinned everywhere else as well that i can see her scaly red skin. she has little bumps everywhere like big hives. Poor girl is miserable. she was better off with the darn fleas. Not sure where to go from here

          14. Lacey says:

            I have a three year old boxer APBT mix named Belle. I rescued her six months ago. I have all of her prior vet records and she was always a healthy well maintained dog. i found a flea on Belle one day and decided it was time to get something. I bought Sentry brand topical. She was deathly sick. my hyperactive dog wouldn’t eat, drink, or get off the couch. she had such bad diarrhea that she would leave a trail as she would try to make it to the door to go outside. I washed her with Dawn in the tub once i realized what was happening. She still had fleas. They itched her so badly she shook her ears to the point of giving herself a hematoma. When i took her to the vet they suggested Trifexis. When we got home I administered the pill. no problems. She was still itching like crazy so i bathed her. I use Richards Organics. Sometimes i will use Avoderm. I am always sure to use tepid water and remove all soap residue. I also change and wash her bedding at the same time. I gave her the Trifexis two weeks ago and she is itchier than ever, like so itchy i cant even reach my hand out to touch her, as the thought makes her start scratching. its all she does, scratch and chew. She scratched herself bloody in the night last night which is what led me here. she is also now missing the hair on her thighs and buttocks. its thinned everywhere else as well that i can see her scaly red skin. she has little bumps everywhere like big hives. Poor girl is miserable. she was better off with the darn fleas. Not sure where to go from here

          15. Selena Coles says:

            I gave my 3 year old pit bull Trifexis after being told by my vet it will not wash off. He did fine til dose 3. He broke out in hives. I gave him Benadryl, and he was fine in a couple of days. Dose 4 he did the same. By dose 5 he has lost hair around his belly, rib cage, and under his front legs. Worse are his feet. He is literally chewing the hair and skin from around his pads and nails. I will be switching back to Heartguard Plus and Frontline or Advantage.

          16. Bonnie says:

            I have a 4 year old long haired mixed baby. I gave her a trifexis on 6/18 she has progressively lost more and more hair. At first it was the scratching then her hair started to mat and I gave her a bath in oatmeal shampoo for dogs. Now she has little hair around her neck and head and the sides of her body are beginning to lose hair as well. Her skin is hot and pink…I kept thinking it was laundry soap, or something else, but everything is pointing back to the pill. I plan to take her to her doctor this week.

          17. Kim says:

            I gave my 6 year old Boxer Trifexis his dose 3 days ago. His hair is falling out like crazy. I am taking him to the vet in two days. This HAS to be a side effect. Needless to say, I am NOT happy!

          18. Kim says:

            I gave my 6 year old Boxer his Trifexis dose 3 days ago. His hair is falling out like crazy. I am taking him to the vet in two days. This HAS to be a side effect. This is the 3rd time he’s had this medication and he didn’t have this problem before. He has thrown up though. I knew this might be a side effect, but never in a million years did I think I might be poisoning my dog! Needless to say, I am NOT happy! We need to get this medication OFF OF THE MARKET NOW!

          19. Jenny says:

            After the 1st dose of Trifexis my dogs hair started falling out as well as severe itching along with lovely diarrhea. It was without a doubt from Trifexis because the same happened with my cousins two dogs. Was it a coincidence that their hair came back in when she stopped using it. I don’t think so! All the best to you and your pup.

          20. Y Berry says:

            We have a 2 year old mixed breed and a 4 year old chihuahua/rat terrier. Both dogs got blisters filled with what appeared to be puss within a week of taking trifexis. The 2 year old also had bald spots on his back. We switched to heartguard and bald spots and blisters have subsided.

          21. Jeff says:

            I have a almost three year old Australian Sheppard/Chow Chow Mix. He has taken Comfortis and Heartgard since I rescued him last November. I decided this month to switch to Trifexis. He received his first dose at breakfast on the 15th of July. I put the pill in with the rest of his food and it is eaten along with the rest of his food during that feeding. I have noticed slighlty more itching but nothing extreme and I have noticed, last night especially, that during his brushing there was quite a lot of hair consumed in the brush. It is shedding season though, so I’m unsure that this is a reaction to the medication. I will continue to monitor my dog and he also has three days a week spent with his personal trainer and some other dogs that do day care as well. Good socializing and excellent time spent with a trainer. As far as Trifexis is concerned, just like any other medication you have to monitor your dog and observe things that are unusual for your dog. Make sure he/she is not getting into other things that could cause bad behavior or mischief that could lead to what appears as adverse reactions to the medicine.

          22. Kathy says:

            I have seen a number of people say their pets experienced hair loss and flaky patches after taking Trifexis. I have a 5 month old English bulldog that took three does of Trifexis. He vomited three hours after the third dose. After the second, dose, I noticed a bald spot on his leg. His Vet prescribed an antibiotic for staph. After 28 days on the antibiotic, we returned to the vet with many more bald spots on his legs, and all over his head. The vet did a skin scraping and diagnosed Demodex, mange mites. He put my puppy on Goodwinol, but the condition only worsened. Two separate vets have suggested Ivermectin, however, there are serious risks if using Ivermectin off-label while on Trifexis. Has any one else had a diagnosis of Demodex after using Trifexis?

          23. Bandits Mom says:

            We started Bandit (7yr) Beagle on trifexis two months ago and three days after he started the first dose I noticed funky bumps under his hair then the hair fell out, I thought it was a bug bite until I found mulitples on him. Near the end of the month the bumps were subsiding but once he had his second does, WHAM bumps again and hair loss, he is going to the Vet Wednesday and I’m going to get him onto some other type of prevention.

          24. Lorena Gamboa says:

            Hello, Debbie, my doggie niece Coco has had a lot of issues with keeping a nice coat. I think this could be due to the side effect warned by Triflexis — pruritis, which is itching. Coco itches a lot on the sides of her body right before the hips. She bites herself a lot because it seems to be a very itchy spot for her. We cannot think of anything else that it can be. I have been eager to mention to my sister that Coco might be suffering from the side effect warned by Triflexis. This is what I think could be a very big likelyhood. First, I am taking the time to read online about other people’s experiences in order to more fully provide my reason for thinking that this issue with Coco’s hair loss is due to the intense itching. I have been really thinking about what it could be, and I really think it’s the Triflexis causing Coco this particular side effect. What else? She is an 8-year-old English Creme, long-haired (not anymore), miniature Dachshund. Now that I see you’ve been having this issue, I do agree it’s very likely culprit. Terrible side effect if, in fact, it could be proved. My sister is very puzzled and disturbed to see her doggie go through that. I hate to see it too. I need to tell her to keep watch each time they give her a new dose to see if they notice the itching to be more intense. Thanks for sharing your story, Debbie. I am sorry to learn you’ve had these troubles. I have two of my own. Whenever anything goes wrong, I just about lose it. Best wishes to you and your doggies!

          25. Wendy says:

            We have a 6 month old German Shepherd. He has been given trifexis since 8 wks old and since that time has had ongoing skin irritation that results in biting and scratching of back, paws – just about everywhere. After reading the package insert and these blogs, I have decided to stop the trifexis…he is due a dose next Monday – to see if the condition is corrected. I also notice that he has episodes of vomiting and diarrhea for a day or so after each dose. Unfortunately, last month I purchased a six month supply of Trifexis, which is not cheap! It also came with a rebate offer which, after several tries and even a call to the company, I still can’t access. So, guess Trifexis was just a very expensive mistake on my part! I wish I had done more advanced research, but was relying on the reader’s recommendation. And she can’t really be faulted as it seems not much is known about side effects of this product.

        2. Barbara says:

          Our 2 Boxers have been taking Trifexis since December 2011. Each of them have been showing signs of weakness in their back ends. When they walk, their back legs slide out from under them. It’s as if they have no control over their back legs. One dog is worse than the other. They are not related, by the way. We’ve had them checked for hip problems, but that’s not the problem. I’ve told our vet about our concerns and have switched them to Heartguard as of this month. Do you have any suggestions?

          1. erin says:

            Barbara – my boxer passed away from myelopathy at 10 yo and that was one of her first symptoms. I think its common in boxers and you might want to check it with your vet.

          2. Very Concerned in Puerto Rico says:

            We gave our little dog (5-9lbs mixed breed) one dosis of trifexis and within hours began to be lethargic and can not keep on her feet. When she stands up, after a few steps, her back legs are the first to give out. And she has a blank stare. Will the sypmtoms subside? How long will it take?

          3. Sarah says:

            I have an 8 yr old pug and a few hour after giving her a dose of Trifexis, she was unable to support her own weight and seemed very disoriented. It took her several hours to return to normal. Also, I have given it to my Pit bull who is 4 yrs and it makes him very “doped ” and sick for 2 days following the dose. I am discontinuing the Trifexis.

        3. Jennifer Bailey's Mom Ft Worth, TX says:

          Bailey is a 6 year old pure breed West Highland White Terrier. She weighs about 17 lbs. We just moved to Texas from Chicago, IL. This is the second month I have given her Trifexus only to have uncontrollable vomiting for more than 12 hours each time. The first time, the vet took her in and gave her fluids for almost a whole day plus anti-nasea medication. They asked me to give her half of a Priolosec this time before administering the dosage. But, my dog is vomiting again all night. The symptoms don’t start immediately but rather about 8-10 hours after the dosage. This is very, very concerning to me as both times my dog is clinging to me like a child and letting me know she feels very very bad by tucking her nose under my arm to hide her eyes. She has thrown up at least 5 times already and the vet doesn’t open for hours. We have always used a private practice vet in Chicago but have recently gone to a chain pet store’s vet. They do not offer her regular heart worm and flea med. So, they switched us to Trifexus. The results are excessive vomiting and shaking and dehydration so far at a minimum. This is not acceptable. Please do not give this medication to your pet without watching them closely for 24 hours after dosage. Bailey will NOT be taking this again.

      2. Matt Baker says:

        My puppy experienced the exact same symptoms after I gave him a single dose of Trifexis. He is a 14 week old German Shepherd. I will never give him another dose. What is the detox treatment??

        1. Katlyn says:

          Keep in mind that puppies when normally receiving trifexis have also just gotten their puppy shots. Our first time using trifexis with our 18 week old lab she had diarrhea and some vomiting because we hadn’t followed the instructions on making sure she had a full meal before taking the medicine. The 2nd time she was perfectly fine. And this time she is lethargic because of all the different vaccinations she received today along with trifexis. The vet said she will be lethargic and lose her appetite. My vet also told me to not worry about what people say on the Internet because it is a case to case basis. In some cases he said adult dogs will have seizures or allergic reactions because they are switching medicine that they have used for years. They say you see a lot less side effects in puppies.

          1. Kathy says:

            I have a 13 week old puppy and my vet gave him Trifexis on Saturday. Six days later( Friday) this week he had a seizure. I thought he was dead because my husband found him stiff in his cage then when I picked him up he went limp. As we rushed to the vet, he started to come to. I was so scared. The vet asked did we have rat poisoning around the outside, but we keep our puppy inside the house and no we do not have rat poisoning outside. He didn’t eat any poisonious leafs or plants and he has been fine. They did blood work and everything came up normal. As I searched the internet for answers this is the conculsion I have found. As from the breeder none of her dogs or puppies have seizures. So I would NOT recommend Trifexis to anyone. My puppy will not get anymore doses.

        2. Candace says:

          My 15 month old French Bulldog became blind on Sunday, it is linked to Trifexis. She has been on it for 12 months. Please don’t use this drug. Mu nephews dog had siezures and died last year and I just found out he was on the same drug. UC Davis Vet Center had linked it to the drug.

          1. Brandi says:

            My french bulldog Rosie, just went blind on Saturday…..She was given a dose of Sentinel on Monday. Not sure if this is linked yet or not…but wondering if your french bulldog recovered or is the blindess permanent?

          2. sandra says:

            My dog is 5 years old and is going blind in his right eye, which I thought was way too early. I have have given my dog trifexis for 2-3 years. He is pretty lethargic also. I now wonder if this flea med has an effect like what my dog is going thru that is very harmful.

      3. Dana says:

        Anna – My vet thought we were crazy when we told him that we thought Trifexis was causing our dog to limp. It was about his second or third dose when he started limping with his front leg. He had trouble with his back knees in the past, but never the front. The vet could not figure out what was wrong and gave him pain medication. At the same time, we started to see fleas on him and wanted to try going back to a topical flea treatment. Within a couple of weeks of going back to the topical flea treatment, the limp mysteriously stopped (and so did the fleas). I was happy at the prospect of not having to use a topical treatment since we have a young son, but not at the expense of my dog limping and having fleas. I can’t prove the Trifexis caused the limp, but it certainly is an interesting coincidence that it started and stopped with the Trifexis.

        1. Nicole says:

          My dog was switched from Revolution, which she tolerated well for over a year, to Trifexis in December 2012. She is a Pembroke Welsh Corgi and just turned five years old on February 8th. Since switching treatments, she has had sensitivity to touch (groaning when we rub her side or belly) and two bouts of horrible hot spots on her vaginal and rear hind leg area. I currently have her in a cone after another cortisone shot and oral antibiotic for yet another infected hot spot. Normally, she is quite energetic and healthy, but she has been demonstrating marked lethargy over the last 30 days. In addition, and like another commenter, she has developed a limp in her front right leg. The ONLY thing that has changed in her routine is Trifexis so I am inclined to take her off. Does anyone recommend a good detox treatment, and should I give her two to three months before I resume Revolution so that she can get this pesticide out of her system? I live in Southern Cal, and we are approaching the height of flea season so I am concerned. Lastly, I have an appointment with her vet Monday because I would like him to file a report with the FDA on this medication.

          1. corgiowner says:

            Just wondering how your Corgi is doing and whether she is doing better off of Trifexis? Curious what you switched to (for heart worm) as I am thinking of doing the same after reading these comments.

          2. Kathy says:

            Our 10 year old Pembroke Welsh Corgi had similar side effects as everyone is mentioning. We noticed it after his 4 th dose of Trifexis. He was extremely lethargic, grimaced with any touch, lost his fur, skin had a foul odor,could not stand on his hind legs (even to go outside) and would not eat. Our usually happy, excited Corgi would not even come out from under our bed to celebrate Christmas! He was usually the center of attention. My vet still thinks I was crazy for suggesting that it was related to the Trifexis. When I called the manufacturer, they said that ” it definitely sounds like a reaction” and offered to refund my money. Since I purchased the medication at through my vet, my refund came through them. They did not seem the least bit happy or interested that I called the company and was getting a refund. Needless to say, we are changing vets. Now, 5 months later, my Corgi is more his usual self. All of the effects have subsided, with the exception of the skin issues. I think that this is poison and I won’t give it to any other animals. I will say that perhaps, it’s not the kind of medication that will work with such wide weight categories for dosages, given the combination of medications. My Corgi was dosed based on his weight, but his body/ organs are not the same size as those of a larger bread weighing the same amount.

      4. Richard Soltys says:

        I had a chi/min pin mix who dad the similar problems with the lehs and than started having seizures. Shortly before he lost his sight. I got him froma shelter and they gave him a clean bill of health . After starting him on Trifexis he went downhill. I feel so bad thinking that I killed my dog.

      5. Kimberly says:

        Anna, how did your dog do after detox? Did the balance in his hind legs improve? My dog has had major balance and coordination problems and he was just diagnosed with cerebellar degeneration at only 1 year old! I have just put it together that Trifexis might have caused this, and then I go out to research it on the Internet and find other people are going through the same thing. Please let me know if getting your dog off Trifexis and doing detox made any difference in his hind leg weakness.

      6. Kimberly says:

        Anna, how is Zipper doing? Did getting off Trifexis and doing detox make a difference? My dog is experiencing these same symptoms. Any feedback you can provide about how your dog is doing would be appreciated!!!

      7. Kay says:

        Anna, what has happened to your schnauzer since you wrote this post? I have a one year old dog that is taking Trifexis and is also experiencing hind limb ataxia and head tremors. I have seem a veterinary neurologist, and she did an MRI and a spinal tap. She told me that my dog has symptoms of cerebellar degeneration. However, he has also had blood work done that indicates he has some liver issues. I am wondering if the Trifexis injured his liver, which in turn injured his cerebellum. I am going to see a holistic vet next week. After your dog went thought detox, did the hind limb weakness improve? I hope you see this post. I am pretty much grasping at straws here.

    2. Dawn cervenka says:

      I have just given my 1 year old LAb mix trifexis and now know that symptoms I’d observed previously are definitly caused by this drug. The first time, I had not reason to suspect the drug and it actually fell of my radar, second time I knew it was the drug. My vet assured me that unless Janx was physically I’ll, throwing up, there was no problem. They also said that lethargic behavior was NOT a symptom. wrong!,,, the third dose wasmjustbgiven and within 2 hours jax is huddled in his bed and can’t lift his head. I have called the er and they confirmed that trifexis definitlyn causes these symptoms. They felt I should bring jax in for fluids to flush his system. I am so torn between spending 350.00 or waiting until morning to see if he is fine ( this was the case the last two times) ! I am so mad at my vet for not being more aware of the drugs issues and confirming versus disagreeing with my observation!!!!!

      1. Don says:

        Same problem as most replies describe. I gave my 16 week old Golden Retriever his first dose of Trifezis last night with dinner and by this morning he was lethargic and could not stand up on his own due to weakness in his, twenty hours after the dose he is more alert. Will not be using the product again.

        1. Kelly says:

          I found this site because my shih tzu was having mucousy poop and some vomiting after giving Trifexis. I tried giving her half a pill two days ago and was going to give her the other half the next day but she is having the mucousy loose poop again. I’m taking the Trifexis back to the vet and switching to heartguard!!

    3. Deborah says:

      I’ve given my 12 yr old dobie mix 2 doses of Trifexis (she was on Sentinel) both times with evening meal. So far haven’t noticed any side effects.

      1. Sue Barrass says:

        Our 2/12 year Ole English Bull dog has been on Trifexis for almost 1 1/2 years. She is pretty listless for about 12 hours so we give it her at night and she is fine in the morning.

      2. cindy says:

        I had my three dogs on front line plus and heart hard for years. They hated getting front line and would literally run when they saw it. Then we got fleas that would not die. I had some advantage from another time front line quit working and applied it to my two small dogs. It only worked on one of them. After speaking with vet he recommended trifexis. My rat terrier and my German shepherd loved them but I had to force feed the jack Russell. I made sure to feed them something they would eat immediately. Lo and behold there are no fleas. My dogs have been on this two months with no problems. I too am nervous about internal meds for fleas. This is why I am reading this because we now have small puppy an worried about putting her on this. My other dogs are 13, 5, 3. I think I will keep other dogs on this and put puppy on topical with heart hard after reading this.

        1. Maria says:

          Gave trifexis for 1st time to my 8month old Lab Shepard because because I’m broke and the vet gave me 1 dose sample free. Read the info on tap, my BO weighed in at 40lbs. today that is a gain of 2 lbs. since she found me during the January freeze in San Antonio Tx… She lives to run. Fed the Trifexis in a peace of raw chicken breast which part of her raw diet and the last 8oz. meal of 2 daily. I ran a search on Trifexis to find all the horror stories here. I will be sleeping with my dog tonight.
          Information on the tablet tap specifies minimum weight of 5lbs. – max of 40 lbs. body weight, 8 weeks minimum age, there is a lot # and Expiration Date of 03/2015.
          I gave BO Trifexis because I’ve seen her eat feces, wood branches, dirt, stuff she sniffs out off the ground. I’m learning to read when she is instinctively just hunting and when she is getting ready to eat some garbage to correct the “Bad Eat” behavior. BO plays almost everyday at the dog park with other big dogs for a minimum of 15 minutes included in 3 daily walks that last at least 45 minutes to an 1hr. each. I will not feed her commercial dog food or treats anymore than I eat commercial process foods, as much as, under my control.
          Same goes to the environment conditions I will expose myself or companion to. I fumigate the yard and don’t let BO out there for days, not the best option but its what I do. I’m looking to select exercise or play time companions with dog owners I come to know as armed with knowledgeable information resources & experience because I need to learn more for my pet & I to protect our health and survive FDA oversights of unscrupulous profiteers and captains of commercialism or just have been drinking too much of their own kool-Aide.
          If your companions are more indoor than out door pets avoid injestible medications whenever possible. If your dog’s heartworm or other worm tests are negative don’t medicate. If you have a small breed family member, what is the weight recommendation on the tab of Trifexis or whatever, pet injestible pesticide you choose and adjust the dosage by cutting the tablet into 4 1/4s or whatever size would be more appropriate for you dog’s weight.
          I’m researching natural spice and dietary alternatives to worm & pest infections prevention among breeders, other dog owners’ forums, its all very controversial and difficult to find the right course of action.
          Its been 4hrs. since I administered the Trifexis, BO is asleep now. I will not be using this product or any injestible product for my dog’s flea control for this I will seek perhaps a topical solution or preferably a natural solution and continue to fumigate the back and front yard. For heart worm and other worm infection prevention I will experiment with apple cider vinegar as a dietary supplement along with periodic fecal tests. Check the following for more info. Thank you all for your experience and my condolences on your companion’s & your suffering.
          Hope Trifexis works for my BO this one time and if it does I would only use it for worm infestation which I hope to prevent without toxic medications, this has to be the last resort. I will report back here should any ill side affects manifest.

    4. M McAlpin says:

      I was wary of Trifexis when we had to discontinue Sentinel for our 12 yr old mixed breed. But vet’s confident attitude convinced us to try it (“if he vomits, just give him another one; if he continues vomiting, discontinue & return the meds and we’ll find another treatment for HW and fleas”). He didn’t vomit after dose #1, and the first month we only noticed his appetite was off, maybe a bit lazy after dosage. We were worried b’c he was at the cutoff weight (60 lbs) btw two diff dosages, but vet tech assured us the higher dosage was the right way to go. We gave him the second month’s dosage yesterday and had to be out for the evening: we ret’d to an unrecognizable dog. Disoriented, unable to move easily, would not eat, could barely walk. He does have arthritis, so we thought maybe Trifexis just made him “lethargic” and prolonged sleep left him achy. We gave him a Rimadyl and ordered more Adequan this morning, which we give him at home in an injection. Appetite cont’d all day to be nonexistent, eyes show pain or disorientation, just not himself. Now I’ve read all these postings and I’ve got to wonder if the mobility issues and lethargy we are seeing were neurological, a side effect of Trifexis! He seems better tonight and ate dinner with the incentive of a little “tuna juice” poured on it. We will never give him Trifexis again, but don’t know what we will give him, and don’t know whether this seeming upturn means he is OK or we should have him checked anyway? We had no problems on Sentinel, ever. Why do consumers have so little info and power in regard to these very expensive drugs we give our dogs (ie, loved ones)? Vet opinons are as varied as info on the internet. We have no idea where to get a definitive opinion. Reading anecdotal stories online seems like a poor research method, but where else can we turn?

      1. Natalie says:

        I have a 7 year old mixed breed border collie and German shepherd. She took the pill 2 weeks ago and hasn’t been the same since. Went to the vets multiple times. Couldn’t find an answer. Finally today we did Iv on her to see if it was any better. Turns out not that much. She’s lethargic and not the same. The doctor finally got to observe her for the whole day and she thinks its neurological. My dog has had several accidents, lethargic, and just not her plain energetic self. We will see if the drug can wear off in 6 weeks…..if

      2. G.oknzi says:

        Google Rimidyl. My yellow lab had permanent kidney damage after use. My vet gave me no idea the potential side affects.

    5. Yvonne says:

      We have a 3.5 year old llewelyen setter weighing about 60 pounds. In the past we tried Comfortis once. Afterward she was practically comatose for several hours so went back to the topical treatments. The fleas have been terrible here where we live so this summer we decided to give Trifectis a try with mixed results. We have given her about 4 treatments. Twice including last night after giving her the pill with a meal, she has had similar reactions – disoriented and anxious. Kept us awake with pacing, standing by our bed, panting, funny look in her eyes. That caused me to check out this site this morning. After two bad reactions, we will not use this product again even though it is very effective for flea control. She ate only a little this morning but otherwise seems ok now.

      1. Jim says:

        We have an eight yr. old golden retriever mix, who has only had medication for ear problem 2 yrs. ago… So we took him to the vet in Nov. for skin problem and was put on trifexis…He had his 2nd dose Jan. 1…Now he is not the same dog and we are sick…He is also panting, pacing, making noises, standing at the bedroom door until we let him outside for the night…He has never slept outside all night before this..Our yard is fenced, but it was 20 degrees last night, so I put him in the back bedroom and shut the door..I believe he cried all night, so got up at 5am to let him out..He came out of the bedroom all confused and we are at our wits end..Going back to vet in Feb. after this pill wears off…we can only hope he gets back to normal…No more trifexis for our dog!

      2. Jules says:

        If your dog reacted to Comfortis, it should have never been given Trifexis. The same flea agent, Spinosad, is in both. I believe after thorough research it is a dangerous poison.

    6. Lee says:

      I gave my 70 lb. greyhound trifexis yesterday. He was lethargic all day yesterday, & today had extremely bad diarrhea. Trifexis was the only variable in his day, so I’m fairly certain that it was the trifexis.

      1. LauraH says:

        Lee, I was wondering if the diarrhea your dog experienced got any worse? Ours certainly did!!

    7. salli says:

      Trifexis is horrid! I have a 5 year old perfectly healthy (once) Havanese. I gave her one dose of Trifexis, she has been going through hell! Diarrhea, weight gain, not drinking water, lethargic, and now they are testing her for Thyroid problems. Everything was perfect in her August chem panel. Started Trifexis mid November… and still trying to get my darling healthy dog back. Vomited only once four hours post Trifexis, lethargic and a bit twitchy. Then the not wanting to eat started followed by colitis looking stool, bouts of diarrhea, and now less than a month later, she is panting, has the runs, acts like she has urgency and then pure liquid Fecal matter. She had perfect stools before this. So far I am at 1000.00 and counting post Trifexis… DO NOT GIVE YOUR DOG THIS DRUG!

    8. Teresa says:

      I have a 9 year-old Shiba Inu. I got Sheila from the shelter and take her there for her veterinary care. She takes Trifexis every month. I coat the pill with peanut butter because she loves it which makes it easy to get her to eat it. I have not noticed any adverse reactions whatsoever since she started taking this medication.

    9. Cate says:

      We have been giving triflexis to our 2 year old Goldendoodle for about 18 months we have had no problems at all and in fact he tolerates the medication better than he seems to tolerate topical flea products.

    10. Scary69 says:

      I have been using Trifexis for over a year on my Toy Poodle and he has had NO side effects. Like it was stated in the article depends whether the pet has has health issues in the past and not all medication will work the same on all pets. Even adult medication does not work the same on all adults, does not mean I will not take it because everyone is different.

    11. Rose says:

      Have 3 dogs, only one moved to Triflexis. 3 year old healthy yorkie cairn terrier mix-9 lbs. Lethargic after first dose – not enough to worry but stuck in my mind. After 2nd dose, effects lasted longer that we thought she might be ill with something else – lethargic, skittish, licking, spacy and sometimes yelp for no reason. Took to vet – thought it was back injury but no real evidence. Steriods, pain killer, muscle relaxer. By third dose, more of the same, took to another vet who “guesses” the same and bumps up medicine for the 3rd time. After more rapid decline, increased spasms, increased difficulty standing, runny nose, spot on lung and ineffective posturing, took to neurologist specialist. She’s in hospital now, decreased platelet, anemic, increased liver enzymes. Systemic conditions masked by Steriods. All vets supposedly did X-ray and full blood panels. I suspect Triflexis has played a bigger role in all this. Wanted to post this in case others are being directed down the back injury route – please get your pup to a specialist if your vet is just guessing if they are exhibiting neurological effects after taking Triflexis. I hope we have made the right move in time – my baby will not get another dose.

      1. Misty says:

        Seriously, my dog has been fighting this SAME thing since January–for 7 months now. But his reaction was to a different topical flea medication with permethrin as the active ingredient. His platelets got so low he had a brain bleed stroke–and has spent the last 3 weeks recovering from that. I tried Trifexis about 2 months ago and he slept the whole rest of the evening. Too scared to give it to him-but my vet says that should be ok to give. I decided to research it BEFORE I give it to him this time–and I am just about sick! I feel like everyone else –guilty for giving this to my dog and he has had a stroke as a result. I know now that I will NOT give him this again—or any other for that matter. 2 different meds with the same issues-I am not trying a 3rd. I think I am going the “natural” way.

      2. Stephanie says:

        Rose, can I please contact you via email? My dog, Baci, was suffering from the exact same symptoms you describe before her red blood cell count dropped to numbers she could not handle… symptoms started with lethargy, unexplained shaking, and she was prescribed steroids to deal with a supposed slipped disc in her back. We had to put her down in October after two blood transfusions and no recovery. I would love to talk to you as her case was never resolved, and until now, I never suspected Trifexis–which I had switched her to a few months previous to her symptoms. Thanks.

      3. Carrie says:

        My precious yorkie has has very similar experiences. I am scared we will lose her. This med has killed over 700 dogs, so far! What more proof do people need? I just signed a recall petition on I pray they Stop this killing spree.

    12. Lori says:

      For the dog owners on here who have had a dog react to Trifexis, my 70 pound pitbull is currently going through this. I have been home with her all day trying to help her. Any advice on helping her get through this? I am so angry I did not research this drug before taking my vets advice to switch my girl to it. I am upset that a decision I made had put her through this. She is an otherwise very healthy and tough dog. This is the first time she has ever had anything like this happen to her. How long will it last? Will the vet be able to do anything for her if I bring her in? I am growing less and less trusting of my vet and am in search of a new one.

      Symptoms: trembling bad every time she breaths in, disoriented, wobbly when trying to walk, she has fallen over several times, trouble using the bathroom, very sleepy, eyes are low (not opened all the way), she has vomited twice and has not eaten all day which is a first in her 8 years of life. When I put her food down this morning, she would pick up pieces in her mouth, then spit them out… at first I thought it was a tooth problem but I have checked her all over, no pain, no ear issues. The ONLY difference is I gave her Trifexis last night, by the morning she was like this. This is her third month on Trifexis. PLEASE HELP, anything to help me get her through this! I called my vet and they said I could drop her off and they would monitor her, well I can do that here. Thank you for any advice.

      1. Carol says:

        I gave my 1 year old lab her trifexis with a meal and within 2 hours she was disoriented, and stumbling. Rushed her to the emergency animal hospital and they have started Ivs and sedative along with a med to help absorb the toxin. I will never give her trifexis again. SHAME on this company. I pray that Ellie will recover with no lasting side effects.

      2. geroge says:

        gave comfortis tablet to tea cup chiuhaha 3.3 kgs. 6 days later confused skittish, when attemt to pick up screams and screams terrified but of what???? dog never been like this before? just took to vet explained all that has changed is that we used comfortis same active ingrediant as tryfexis which is (spinosad).

        we thought he had back problems cannot be picked up . the vet thought back neck problems. Vet came up with nothing . it doesent take a genious to work out the dog is suffering neurological side effects from this drug. any drug crossing the blood brain barrier has effects. whether inhibiting or promoting. the dog is still spaced out , seems depressed axious and frightened. any attempt to pick him up reults in him completely stressed to the point of terror. very loud screaming.

        dont give any flea treatments to your dog containing (spinosad). we hope our dog gets better dont waste time with vets or safety labels . drugs is buisness just look at proscar for men and neurological side affects . fda approval means nothing . dont give flea treatments to your dog containing spinosad .

    13. Carol says:

      I foster a 1 1/2 yr old Lab Pit Mix. It took me 2 months to figure out what was wrong with him. After his initial dose of trifexis he started vomitting and had diarreha. I didn’t figure it out until the 2nd month. Same reaction and became unstable in moods both times. He will no longer take this product because his behavior and physical reation was no like this on Iverheart.

    14. Carol says:

      I foster a 1 1/2 yr old Lab Pit Mix. It took me 2 months to figure out what was wrong with him. After his initial dose of trifexis he started vomitting and had diarreha. I didn’t figure it out until the 2nd month. Same reaction and became unstable in moods both times. He will no longer take this product because his behavior and physical reation was not like this on Iverheart.

    15. Dave C says:

      Our 1.5 year old scipperki start diarrhea within 3 hours of taking Trivexis, this lasted for 2 days and eventually elevated to hemoragic gastroenteritis neccessitating an overnight trip to pet emergency. $1400 later she is now recovering. We have no proof the medication did this, but she has always been very healthy, has regular vet vesits, and all vaccinations. All tests at emergency found no other cause (ie: parvo, blockage, infection, injury, organ problem, temp, etc) . We will not give her trifexis again, and will not give the remaining pills to any other pets, although not scientific, we know our dog and trully feel her problem came from the trifexis.

    16. Greg Smith says:

      We have a five year old Puggle, five hours after taking Trifexis he stopped breathing, rushed him to ER VET his throat where it enters his chest inflamed so much it cut off all his air. He could not breath, worst thing to have to watch. After over $5,000 in CT scans, test and oxygen he pulled through took about 72 hours. The VET ER docs could find nothing to have caused this, except the possibility of a drug interaction from Trifexis. He can get worms before I will ever put him back on that drug. There are way too many postings of health issues with this drug for the manufacture and or the FDA to do nothing. I am not one to sue but I’m contemplating filing CLASS ACTION LAW SUIT AGAINST Elanco.

    17. Stephanie says:

      Siberian Husky, 4.5 years old
      Vomited 4 hours after Trifexis.

      First dose in February 2013. She wasn’t eating well afterwards, but she was also given an antibiotic and prednisone at the same time and then was on too high a dose of levothyroxine. All of these might have affected her lack of interest in food, so I can’t say it was the Trifexis.

      Second dose in March 2013. Again, given with food. She vomited a LARGE amount (both morning and late afternoon feeding) about 3.5 to 4 hours after ingestion of Trifexis.

      Thank you.

      P.S. I will be starting her back on Frontline or Revolution.

    18. Terry says:

      JaZmine is a 3year old 83lb Weimerana. I started Trifexus about 1 1/2 years ago. Not knowing what the heck was going to happen. I began noticing her upset tummy right after taking the product and then the back legs weakening for about a week or so after dosing. Since then she has had 4 seizures, with the last one finally being directly connected to the timing of her pill. This last seizure scared me for it was over 4 minutes. Since the seizure she’s been to the veterinarian and has been diagnosed with epilepsy. She now is off the Trifexus for the past month and is taking phenobarbital to address the seizures. The coughing, which I thought was allergies has calmed down. Now the question remains, can I ween her off of the phenobarbital since I am 100% convinced the Trifexus was directly linked to the seizures, coughing, weak legs and vomiting. JaZmine is my very first puppy and I would hate to think that I did this by trying to control fleas. She’s my best friend and companion and don’t quite know what to do………….

    19. Derek says:

      Horrible medication. Taking my dog off. Been on it two months, horribe itching, red bumps all over her back. Never had this before this medication. She is a purebred wirefox, 8 years, and no medical issues before this.

    20. Hope M says:

      I’m sorry to hear about all these dogs experiencing side effects =( Our mini schnauzer has been on trifexis since she was old enough to have it, and we’ve never experienced any side effects. She’s 3 now and the only time we stopped dosage is when she was pregnant (she gave birth to 7 healthy mini schnauzer pups!) I guess what works for some, just may not work for others. =/

    21. brenda says:

      my dog rocky had seizures and kidney damage right after a dose of it. my other two dogs were not affected but
      vet was to report it to authorities. I would never use this again, a 45 lb dog part Lab who never had a reaction in his 8 yrs should not have suffered like this.

    22. Kim says:

      For those that have had serious issues with Trifexis…PLEASE file a report with the FDA. You can do this at This is the only way the product can be tracked and taken off the market if necessary! Thanks

    23. Lindy says:

      I almost lost my dog last week. He is a 10 year old Fox Terrier in great shape and until last week, very healthy. He had reactions to Trifexis 2 prior times and my vet told me that it was “rare” ( I have since seen stories after stories like mine so “rare” it is not) that he was vomiting the pills but to try to split the pill over two meals. I practically had to stuff it down his throat last Sunday as he continued to gag it up. I should have known and now feel like I was feeding him poison. By Monday morning, he had thrown up a dozen times and in between he was confused, shaking almost like he was having a seziure and seemed to not remember what his back legs were for. He started foaming at the mouth and was having trouble getting air. This went on for a horrible 6 hours. I called the vet who again told me that they had never heard of a reaction like that. I told him that he should start reading the websites….and he is no longer my vet.
      I am with the others who write here, why do vets give this medication when they know the potential of killing our pets. Mine made it through but still has a shake in his back leg.

    24. Sarah says:

      I gave my 4-year-old golden retriever, LJ, Trifexis two weeks ago. I’ve noticed him scratching and losing hair much more than he used too. I was very hesitant to give this drug to him because it just seemed like a lot of medicine in one pill. Because the topical flea control isn’t working, are there any other options?

    25. Bonnie says:

      I have a 3 yr old rottie and she started taking trifexis about 6 months ago. It has been fine but the last dose I gave her which was Friday has me wondering if it isn’t the issue with the problems she has had the last couple days. She is a little lethargic, no diarrhea but has vomited a couple times a day the last couple days. She seems fine other than the slight lethargy and vomiting but I’m wondering if I continue giving it to her will the symptoms get worse with every dose? I will be consulting with my vet to find out if there is an alternative. I don’t believe I want to give her any more trifexis.

    26. Don says:

      I took my 8 year old female boxer to the vet for a check up. Afterwards our Vet recommended Trifexsis since it was time to administer Heartgaurd Plus, which my dog has been taking with no obvious issues. So we purchased it and gave to our dog that day 23rd of October. The morning of the 24th my dog didn’t want to get up to go out was very lethargic. This is completely the opposite of her. When She did get up she stumbled in to walls fell flat on her face. Once she got her footing we went out. Outside it seemed as If she was patricianly blind and drunk. Having trouble seeing and listening hard for our voice. Inside just sitting around we noticed her drooling from one side she never drools and her face possibly saggy on the same side. No interest in playing. This is very odd for her. She is always full of life. We took her to the Vet today the 28th and our Vet thinks she had a mild stroke. Although she has gotten better in controlling the dizziness it is obvious that she has stroke like symptoms. She is a completely different dog. The only change in her life was the Trifexsis. No diet, Nothing else. I would never give this to any animal again!!!

    27. Keira says:

      I am leaving this as a reply because I cannot find the leave a comment link. I hope everyone can see this. I have a shih tzu that is 10 months old named Khali. First gave her Trifexis last month and the vet gave us the puppy does that is for dogs 10 pounds and under since she is so small. We didn’t have any problems. When I went to the vet this month they moved her up to the 10 to 20 pound dose because she was right at 10 pounds. Since I gave her the dose two weeks ago she has thrown up four times and sometime starts breathing funny. Almost like a child with sniffles from crying. Two quick breaths before a regular breath. I think maybe it is because of the higher dose of Trifexis. I am not going to give it to her next month and see how she reacts.

    28. Steve says:

      after reading more than a few stories about how the dogs (like mine) got disoriented, vomited, seemed out of it. THIS CANT BE A FLUKE! More than several times, reading these comments , it was as if they were telling my story. My dog is a 9 yr old half shih tzu half pekingese about 12 lbs.

    29. Fran says:

      I gave this to my dog and within three months I noticed she was having tremors. I stopped the drug but didn’t make all the symptoms go away. She looses her balance now walks into things and overall health has went down hill she can’t see like she could before and will just start walking around the yard with no aim. She was a healthy 7 yr old boxer but she isn’t any more. I told my vet that I wanted something else for her that trifexis was a nightmare they gave me something else and pretty much didn’t address the issues.

  2. Sandra says:

    I’m not having a problem like I had with Comfortis. My girl is a rescue mixed breed, lab, shepherd,chow, about 60 lbs.

  3. Wanda says:

    My dog has been on Trifexis for a year with no problems at all. She weighs 6 lbs. As said in the article, with any medicine, some side effects can occur. Many of these side effects can occur from taking just heartworm medicine as well. Every animal is different, finding the one that is right for your dog, is what is important.

    1. jessi says:

      I have a 7 lb. bichon frise/shih tzu mix, she is 2 years old and has been taking Trifexis for 1.5 years with no problems other than occasional vomiting of saliva, unsure if it is related.

  4. THRISHA says:

    I have two dogs who switched to Triflexis long before the shortages. One is 5 and the other is 6. They have had absolutely no issues. It has been well over a year at this point.

  5. Stacy says:

    I have a 18 month old male Pomeranian, named Jax. He was on Frontline and Heartgaurd. I changed him over to Trifexis, 8 months ago. Jax has not had any problems while being on it. I have not noticed any side effects what so ever.

  6. Leslie says:

    My two Cavalier King Charles Spaniels have been on trifexis for a year now and have had no problems at all.

  7. Jill says:

    My dog is a 2 year old australian shepherd. I started giving him trifexis about 3 months ago and I have never noticed any kind of reaction on him.

  8. Hannah says:

    I worked at a vet when the product was introduced to me. Both my American bulldog and dachshund are on trifexis. I’ve never had problems at all! I love this product it is absolutely amazing. Follow directions on the box!

    1. vicki says:

      my dog is a 3 1/2 year old aussie – she’s been on triflexis for 4 months with absolutely no change in behavior, appetite, energy level or anything. i did see one flea on her once, however it was very close to her next dosage due date and for all i know it would have died shortly after my spotting it on her. so far so good for us.

  9. Adam D says:

    At the emergency vet right now with the exact symptoms as the scary Internet story. Lethargy… Staring at the ceiling and shivering. Not eating. 2 yr old Australian Cattle Dog

    1. Kat says:

      my female cattle dog had the same symptoms, will never give my dogs that garbage again

  10. Maria S says:

    We gave our 18 month old shorkie his first dose of Trifexis since sentinel was no longer available. Within 5 to 6 hours of taking it our dog vomited and was extremely lethargic and had no appetite. Symptoms continued for approximately 36 hours. We never had any side effects with sentinel.

    1. vicki says:

      put my 3 dogs on trifexis for the first time on Nov,20, next day all 3 dogs no appetite. a few days later my little dashound was vomiting, still no appetite and lethargic. had her at the vets yesterday. and she’s back today, they are giving her fluids and antibiotic’s, something has caused problems with her liver. the vet said it could have been something toxic. after reading about the rumors on the web about trifexis. it has me worried. I don’t think I will use this product again.

  11. Adam A says:

    We have 3 dogs, all turn 7 this month, that we just gave Trifexis to for the second month. The Australian Shepherd and one of the Jack Russell brothers are fine but the one became lethargic and violent shaking. He won’t eat or drink and his pupils are constricted. He is representing neurological symptoms, but the emergency vet told us not to worry unless he is vomiting. It has been 19 hours since we gave him the pill. We will not be using Trifexis again and hope that we can continue to get Sentinal in the future. We have used that for years and never had any problems!

  12. Wendy says:

    We have a 10 month old boxer boy who weighs 65 pounds. I gave him Trifexis for the first time yesterday afternoon, and he seemed fine last night. This morning when he got up, he was very lethargic and droopy and when I fed him, he threw up within about 5 minutes or less. I tried feeding him again later in the day, and he again threw up right away. He is drinking fine, and seems hungry, just can’t keep it down. I took him to the vet and they suspect Trifexis was the cause. Aside from lethargy and vomiting he seems uncomfortable but no other symptoms.

    1. Mojo says:

      My 2 year old Boxer has the same symptoms when I gave him Trifexis. He cannot keep water or food down and just seems out of it for a day or two. Have you found something that works for your dog?

  13. steven says:

    My vet suggested Trifexis, and stupidly, I gave it to my dog without researching it. My dog is a 60 pound pit-lab mix and was almost a year at the time. Within about two hours, she started vomiting nonstop. First we thought it may have just upset her stomach. This went on until the next morning. Of course we took her back to the vet, who said this was most likely a reaction from the Trifexis. Not only was she vomiting, but she was extremely out of it, and wouldn’t eat or drink. She also wouldn’t focus on us or anything around her. This subsided over a few days, however, it took a few days for her to show an interest in food again, and this is a dog who is usually always hungry. Her side effects were mild compared to many that I’ve heard about, but it was scary enough for us. We will never give her Trifexis again after her reaction.

  14. Helene says:

    I have 2 mini poodles and in March accidentally gave both an overdose as my vet filled the Rx incorrectly. My female who weighs 20 lbs. suffered the worst and Elanco confirmed it was 3 times the amount, but she seems to be ok now. My male who weighs 30lbs had no visible side effects, but also overdosed as well. They have each had 2 treatments since and seem okay, but I know long term toxicity and side effects could occur, you never know when. Last night my male appears to have had a seizure, 3.y5 ears old and never had one, the coincidence is too close not to further investigate. My breeder warned me against topical treatments given possible liver damage, why I went with a pill. I’m wondering if anyone else had a similar experience. Elanco claims it should be out of their system from the initial OD, but what if damage was done during and just coming forward?

  15. Andrew says:

    I sometimes wonder if the repeated “my dog vomits” stories are posts from the drug reps of other heart worm/flea medicines. Some of these posts look suspect. Then again, the only people that will find this page are the ones suspecting problems ( or looking to perpetuate the rumor).

    All that said, we have a 6 year old golden retriever rescue who had heart worms ( treated successfully ) and he has allergies. He eats the best primal diets a dog could eat. No grains, no wheat, nothing. I’m beginning to suspect Trifexis. I’ve noticed the last two months that he gets red, itchy bumps on his skin within days of the dosage. His ears start itching him like crazy so much that he tilts his head.

    I think we’ve administered our last dose of Trifexis.

    1. Matt Baker says:

      My 15 week old German Shepherd puppy has experienced the same side effects as your dog as well as other side effects mentioned on this forum after I gave him a dose of Trifexis. I will not be giving him another dose. Good Luck!

    2. Kay L says:

      My 2 year old Golden has developed horrible skin allergies w/ red raised bumps, red skin, and constant scratching in the last 6 months. I am now trying Chinese herbs, homeopathics, probiotics and far he continues to have them. Reading the couple of comments on other dogs, possibly the Trifexis is the cause. It’s administration would coincide w/ these horrible skin allergies.

    3. Jill says:

      Our 7-year-old, 9 lb, very hairy hairless Chinese Crested female had a similar skin reaction. She, too, has a grain-free diet. She had been taking Trifexis for several months, and I am embarrassed to admit it took me that long to notice the cycle of intensity to her symptoms. She started scratching and licking her skin, even digging in to bite at several patches on her back. Our vet did not determine a cause, but gave us a couple meds for any possible infection and for the itching. They had no effect. Once we realized that the intensity of the skin irritation, with incessant licking and biting, was in the days following a dose, we stopped the Trifexis. That was November 2012. It took a couple months for her skin to clear up, but all is well now. Interestingly, our 8-year-old, 14 lb, very hairy hairless Chinese Crested male did not exhibit such symptoms, but we discontinued his use of Trifexis as well.

  16. Elisha Skeen says:

    We have 6 dogs, 4 boxers and 2 Boston terriers. We switched to Trifexis about 3 months ago. Within 8 hours all of our dogs were lethargic and drooling more than usual. Our 10 year old boxer, Bud started having tremors that night, was unable to focus his eyes, and having trouble standing up. This progressed to an actual seizure the next day. He was confused and irritable for days afterward which led to a horrible fight between him and our other male boxer. I realize not every dog will have this reaction to Trifexis, but I think its important for people to know it happened to my dog and could possibly happen to theirs. Bud is fine now, no lingering effects, but back to Heartguard and Advantage for all our dogs!!!

  17. William Bittner says:

    My 9 and a half year old Border Terrier (18 lbs) was switched from Sentinel to Trifexis two months ago. He had no problems with Sentinel. He has had two monthly doeses of Trifexis and exactly twelve days after taking them each month he has had a seizure. He has had no other history of seizures and is active and in good health. I hesitate giving him anymore Tifexis, is their another alternative to Sentinel?

    1. Steve Walls says:

      I have a 105 lb German Shepherd 4.5 years old and, an 80 lb Black Lab 3 years old. We switched to Trifexis 3 months ago. The lab has had no issues, but the German Shepherd had a seizure 3 weeks after taking his second dose. 2 weeks after his third dose he had another seizure. This dog had no history seizures. After discussions with the vet We had blood work done, all results normal. Currently both dogs are off trifexis we are keeping the shepherd under close supervision. We are planning a minimum 90 day waiting period in order to get a reasonable baseline. Further diagnosis will require time, however neither dog will be getting any more Trifexis.

  18. Gary says:

    • Your dog’s breed and age. Rat Terrier Seven years old
    • What side effects are you seeing? Dog passed away
    • How long after giving Trifexis did you see the side effects? Thirty minutes
    Lilly had her rabies vaccination and wellness checkup April 2012.
    Previous meds Iverhart Plus which was what all 3 of our dogs were taking w/o any issues.
    Switched to Trifexis October 2011. Killed fleas in one day off the Yorkie was very impressed with the product. Gave product to all dogs up to June this year. In June had a new refill for Lilly (she is >20lbs the other 2 are<20 lbs.). They all ate their evening meal and then took their meds.
    Thirty minutes later Lilly let out a scream that was almost human sounding jumped up and fell on the floor with her mouth open, tongue out and eyes rolled back. A few minutes later she revived and seemed ok. Contacted after hour ER vet and was advised that if she had not vomited to go ahead and watch her. Same advice from our vet the next day. Everything seemed all right she ate and drank but on the 3rd day she passed out again with the same symptoms as before then revived started to shake and tremble very violently. By the time I got my car keys (less than a minute) to take her to the vet she had fallen over and passed away.
    The other 2 dogs did not show any signs of being ill. All total the 3 had been taking Trifexis for 8 months w/o issues.
    I have no idea if it was caused by Trifexis or what but I did return the product to the vet. I can’t take a chance with the other 2 dogs.

    1. Will says:

      Ilver hart has ivemectin in it. Ivermectin is potentiated by spinosad in trifexis and will kill your dog. Not a theory -says so on box now . Our lab spent 3 days on a ventilator in a coma w ivermectin toxicity after he took trifexis. Same symptoms listed here but far more aggravated. He stopped breathing. Mind you- this was essentially our (vets) fault as it says so on box. 5000 later he is ok. Collies cannot metabolize some components of these meds too.

  19. Robert says:

    have a 2 year old pit bull. gave him trifexis and a day later he is still sick. lethargy, loss of appetite and vomiting. will never use this product again. this stuff is seriously poison.

  20. Hannah Segars says:

    I have a 16 month old boxer. We gave him trifexis for the first time last night. He took it fine, this morning my fiancé got up to go work and noticed he was acting a little drowsy but thought nothing of it. When my fiancé returned from work at 2:30, oleo had pooped (no diarrhea), peed, and threw up in the floor. All of which is not like oleo. When he went to the bedroom he found oleo laying on the bed lethargic and drooling really bad. We took him to the vet and the vet suspects trifexis and gave him zofran for nausea. Since then, oleo has gotten more lethargic, can hardly open his eyes, has an occasional weird jerk motion in his head, can barely stand and is now beginning to randomly cry out or cry out when I touch him along his upper back along his spine. I’m planning on taking him to the vet in am if I don’t rush him down there tonight.

    1. hannah says:

      My 11 week old puppy is having basically the same symptoms. We gave him his first dose on wed, and fri morning woke up to poop all over our bathroom (not like him at all.) He acts hundry but after he eats, he throes up. The only difference I’ve noticed from reading all yhe posts is he seems like hes constipated. I will be calling the vet in the morning and never using trivexis again!!

  21. Barbara says:

    charlie is our 3 year old jack Russell terrier… This is his third month on Trifexis and the symptoms were frightening (loss of coordination, violent shaking, eyes closed and arching head back, smacking gums (nauseous), by the time we got him to the ER vet his heart rate was 220… After evaluating him, they put him on IV to hydrate and acepromazine to calm him so he can sleep through this TRIFEXIS REACTION. Never ever again will I give a dog this drug. It’s more than Internet hype saying its dangerous.. My dog is in the emergency hospital ICU as I type this…

    1. Nancy says:

      What’s the update on you dog?

  22. Teresa says:

    My vet recommended Trifexis yesterday when I took my male pup in to be neutered. Thooght I’d do some research before picking him up this afternoon. Don’t think I am going to go with this product although the vet is pushing it rather hard.

  23. kanmar says:

    My ten year old 25 pound Beagle, Barkley, has been on Trifexis for about ten months. Last month after I gave him his dose he began to exhibit neurological symptoms: lethargy, confusion, weakness in his left hind leg, trembling, and general changes in his normal behavior. He began to go downhill after that point, barely eating, and not leaving his bed. I took him to the vet who tried to come up with many reasons why it couldn’t be Trifexis. She said that if he wasn’t vomiting it had to be something else. She gave him some IV steroids and a course of cortisone pills to do at home. After a couple of days Barkley began feeling better and I thought that the vet was right when she said it wasn’t Trifexis. Two days ago I gave Barkley this month’s dose and he soon began to exhibit the exact symptoms as last month, only more severe. I’m taking him to the vet this afternoon, and will be a little more forceful about Trifexis as the cause of his symptoms.

  24. Jean Ayers says:

    I just want to thank everyone for taking the time to write in their feedback on Trifexis….I just returned from the vet with
    Trifexis in hand for my Great Pyrenees. He has flea allergy and
    one flea bite creates much hair loss and intense biting and scratching. I’ve used Revolution without good results so the vet
    recommended Trifexis…
    After reading all the feedback I’ve decided I will not be taking
    any chances with my dog….not sure what I will be doing but I am certain I won’t be using Trifexis….

    Many thanks to all who shared their experiences….

  25. Susan says:

    Gave trifexis to my mother’s small sheltie/pomeranian mix (4-5 years old) when he was visiting with us about 10 days ago. His weight (21 lbs) pushed him over to the next higher dosage and I was a bit concerned as he has sometimes gotten sick if he has interceptor and frontline on the same day. He seemed okay at first and then had a loss of appetite; still drinking water and otherwise acted fine. No vomiting until about four days later when he began eating sporadically. He still is not back to his regular feeding schedule (twice a day) but is now eating in the morning and still drinking water. He has vomited a couple of times during the night since he has gone back to eating regularly (bile, since there is no food in his stomach). I contacted our vet who recommended chicken and rice until his stomach settles down. We obviously won’t be giving him trifexis again, nor will I be giving it to my own dogs. I have also contacted Elanco Animal Health as outlined on the trifexis site ( to report the adverse reaction.

  26. Kayleigh says:

    I gave by 8 year old boxer/pit mix his first dose of Trifexis yesterday. Today he’s been very lethargic (so much so that he does not want to go outside), nauseous, and occasionally winces as though he’s in pain. He’s still eating and has not vomited, so I’m hoping his discomfort will pass with some rest. If it gets worse we’ll be heading to the vet. I was reluctant to try Trifexis in the first place and I doubt we’ll be giving it another shot.

  27. Ellen OBrien says:

    We adopted a Pembroke Corgi from a shelter. As part of his initial exam by our vet, he was prescribed Trifexis. Since he had already been dosed in the shelter, we waited a month to administer the trifexis. He vomitted the first dose so was given the second dose as per patient instructions. This morning hewas lethatrgic so I called the company to report the side effects. They were quite ready to imediately refund my money. Called the Vet Clinic to explain what had happened. As the day is progressing my corgi is getting increasingly more lethargic, breathing hard/panting and fairly unresponsive. We will NOT be giving Trifexis to any of the other pets in my home. It is “wait and see” whether we take the corgi to the vet this afternoon just to make sure this is a “normal adverse reaction” or the side effect is as serious as it looks.

    1. Jarrad says:

      Sorry to hear about your corgi. We have been giving our corgi Trifexis for the last 5 months. We were a little skeptical after doing our research and seeing the horror stories but we monitored him heavily after the first dose and have seen zero side effects.

      It has worked so well in fact that we didn’t feel the need to use Frontline anymore. Before, we had him on the Sentinel/Frontline combo.

  28. Kim W. says:

    Gave my quite healthy 14 yr. old female lab mix her first dose of Trifexis about a week ago. She’s been a little droopy since, but it’s been very hot here too. Then this evening when we went for our usual sunset walk, about 10 minutes into it, she wasn’t able to continue, she laid down and wouldn’t get up. I had to carry her home. Her gums were very pale, I thought I was losing her. After an hour or so of resting she seems to be recovering, her gum color is much better, and she has gotten up and walked around a little; but still isn’t quite right. Trifexis to blame?? Don’t know, but if she survives, don’t think I’ll try this stuff again; especially after reading about all these other adverse reactions. (This dog has never had a reaction to HW / Flea preventive before.)

    1. DrMarie says:

      I’m sorry to hear about your dog. In this case, I am guessing that the side effects are not related to Trifexis. You may want to have your vet take a look at your dog. The symptoms sound similar to either a bleeding spleen tumor or a serious heart issue. Hopefully she can be seen soon, and hopefully she is ok!

  29. wendylynn says:

    I took my four yr old collie for her yearly checkup last week. My vet is also out of the interceptor (I dont give products with ivermectin to my dog). My vet suggested I switch to Trifexis and I could forgo the “oil” ( K9 Adavantix 2) that I use topically for flea/pest control. My dog threw up several times starting about a half hour after giving her the pill. I gave her food with it, just like my vet told me too. She was also lethargic and didnt want to eat anything until the next day. I will not give my dog Trifexis anymore. I am returning the remainder of the prescription I have. I will cont to use the Advantix 2 and use the remainder of the interceptor pills I have left, next month.

    1. DrMarie says:

      Don’t be too afraid of using Ivermectin. Here’s an article I wrote about some of the misconceptions out there in regards to Ivermectin: Is Heartgard safe for collies?

      1. Gary says:

        Misconception? I don’t know about that. Washington State University, which spearheaded the MDR1 study publicly stated in the beginning that any dose of Heartgard was harmful to the herding breeds with a 75% occurrence in Collie’s. they have since revised their conclusions. I strongly suspect this change of heart on their part was due to pressure from the companies that use Ivermectin as an active ingredient. Money comes first and unfortunately our dogs come second. I have seven Australian Shepherds. Years ago, when I got my first Aussie, I hadn’t ever heard of the MDR1 mutation and apparently never had my Vet at the time. He slipped my Aussie puppy a Heartgard cube before I even realized what had happened. That night I thought my dog was going crazy. He began pacing, drooling, and snapping at the air as well as vomiting and diarrhea. It only lasted that one night but that was enough for me to realize that this wasn’t something he should be getting on a regular basis. I fired that Vet and found one that knew something about MDR1. It will amaze you how many don’t know anything about it. My new Vet switched my dog to Interceptor and I’ve never experienced any side effects since. All my subsequent Aussie’s have been on Interceptor since they were old enough and I’ve never had any side effects with any of them either. I am a strong believer that any dose of Ivermectin is harmful to a MDR1 positive dog and I speak from experience.

        1. DrMarie says:

          Do you have a link to this statement from the University? Thanks.

  30. Daniel says:

    Gave my lab/collie trifexis according to the directions and he was a little lethargic the first night. The next morning, he didn’t want to get out of bed. I finally got him up and walking around and good enough to eat breakfast, but he is still very lethargic.
    My vet is excellent but this is a let down. I had thought they would have researched this (like I should have) before selling.
    Anything that makes your dog feel this bad is not good for them.

    1. Gary says:

      I think a lot of their “research” is conducted with the unsuspecting public.

  31. Shirley says:

    My 7 month old very happy, active and healthy lab/pyrenese mix has been at the emergency vet clinic since yesterday morning. I gave her Trifexis at 8 pm the night before. She was fine when we went to bed. However yesterday morning she was unresponsive and comatose, I took her to my regualr vet who stated she she go the local emergency clinic so lab work could be done immediately. She remained comatose for 24 hours. The emergency vet contacted the Trifexis manufacturer and was told that comas are a known side effect of Trifexis as the main igredients retain a subtance called GABA in the brain which induces unconsiousness, The trifexis rep also stated that most times this sde effect lasts 48 hours and that oftentimes the dogs have a full recovery without organ or brain damage. The emergency vet administered 2 lipid IVs to bind the active ingreditents of the medication as they are fat soluble. As of today my dog has shown some inprovement but is not of out the woods yet. Her eyes are different and she has some neurological impairments. I am out thousands of dollars for this emergency treatment and I am a retiree on a fixed income. In addition I am heartbroken over seeing my dog suffer. Does anyone know an attorney who might consider a class action lawsuit. This has been a heartbreaking experience and I still do not know what degree of recovery my dog will have.

    1. shirley says:

      the vet at the local emergency vet clinic stated that collies and shelties have a gene mutation that causes severe reactions for these breeds when given Trifexis.

      1. DrMarie says:

        I think there may be some confusion there. Many collies and shelties have what is called an MDR1 gene defect that makes them more sensitive to ivermectin and milbemycin than other breeds of dogs. Even though there is milbemycin in Trifexis it is in extremely small levels that are definitely safe for collies. You can read more about this here: Are Heartworm Medicines Safe for Collies?

        The main concern with Trifexis is the other ingredient, Spinosad. There is no evidence I have seen so far to show that Collies are more sensitive to Spinosad than other breeds.

    2. Matt Baker says:

      If you find an attorney to work towards a class action, let me know because I would be willing to participate. Email: I’m so sorry that your baby had to suffer.

      1. Adrian says:

        This is very scary. My frenchie, Claude, experienced same shaking, straring at ceiling, lethargic symptoms last night. He had done this before and after $600 of tests at the emergency vet, the vet found nothing. I asked if it could be due to the Trifexis, but he said no. Claude normally takes Sentinel but since it was on backorder the vet prescribed Trifexis as replacement. It all makes sense now after reading everyone’s experience. Thank you to everyone for sharing your details. Say NO to Trifexis! I’ll be calling the manufacturer today.

        1. Brooke says:

          I had a 5 year old bull mastiff /pit bull mix. He was perfectly a happy healthy dog. The sunshine of my life. I had given him two doses of trifexis. I had to put him to sleep after he suffered 3 major seizures in an 8 hour span….. This happened out of the blue, no previous seizures or signs of epilepsy m… Vet did an “autopsy” of sorts and she found a mass in his belly and pretty much said it probably metastasized to his brain causing a brain tumor….. Here I am now 2 months later, devastated, holding my head in my hands as I read these posts….. I poisoned my best friend in the world with trifexis . Please let me know about a lawsuit. It’s not about the $$$ for me. They won’t stop making and administering this drug until something happens….
          RIP Hando ~I am so sorry.

      2. Karla Jones says:

        I would also be willing to participate in a class action suit.

  32. Elizabeth says:

    WOW! I am almost afraid to give my Australian/Jack Russell Breed (I know weird breed but such a great dog) the trifexis again. She has been on it for a year now I have not seen a problem at all. I give it to her crushed up inside a can of pedigree wet dog food. She weights 64lb & loves to swim in the river. It was a great thing to give her considering she always was jumpin in the water so the topicals (frontline, advantage) never worked.I have even noticed that if a tick bites her it will instantly dry the tick up & it dies?! She was tested for heartworms & a full exam before she was given the trifextis. I am soooo sorry & my heart aches for the people who has lost a member of their family from the result of this pill. But my dog as done really well with it BUT the first sign of a side effect I will stop giving it to her! After her bein on it for a year so im goin to keep giving it to her :-/ but the first sign & she will be getting something else for protection. <3

  33. Jeannette says:

    I have been giving TriFexis for a couple of months now. I have 3 kids, 12 year old Airedale Lab mix with cancer 95 pounds, 4 year old Airedale 65 pounds, Cane Corso Mastiff/Lab mix 18 Months old, 90 pounds. I know right, he outwieghts the Airedale. The older pup doesn’t have an issue eating that huge tablet. The other don’t do so well with pills. I managed to get it down by breaking it up and giving it in pieces, wrapped in cream cheese. Last couple of months they got the single dose over two days. This week, it was one tablet all in one day. Well the puppy has been yacking up meals and has really bad diarrhea. I gave it with a meal, but he is having issues. Fed him only brown rice in chicken stock and Pepto and he seems to be coming along. Also gave him Lactobacillis Acidopholis for tummy.

  34. Pablo says:

    Dont give your dog Trifexis. Yes, there is a lot being said online about it..i didn’t know about any of it until i saw side effects in Frank and i googled it. He hasn’t been eating well since he took the pill; he would never leve a kibble and now doesnt care when i pur him his bowl. This morning I woke up to him with poop everywhere in his crate (poor guy couldn’t hold it through the night) he was covered in a mix of diarrhea and drool, his skin is all red and hes got a sore on his nose. He looked terrified. Hes OK, not lethargic or acting weird or anything, the pill is just messing him up. So…just dont give Trifexis to your dog. Dont risk it. Wait for frontline to come off backorder.

  35. Mary Sangrey says:

    I have two four year old, healthy, fit Siberian Huskies. Like most this year, we were’t able to get our usual heartworm medication so our vet recommended that we try trifexis. The first month we noticed that several hours after giving them the pill both were lethargic, certainly not acting normal. The one in particular seemed particularly out of it – drugged – but after about 24 hours both seemed find. The next month was a different story. We gave the meds in the morning. Upon returning home from work in the evening both were not normal but the one who reacted more the first time was clearly not well. He was beyond lethargic, struggled to keep his head up and was not responsive. Normally upon returning home in the evening we go for an evening run and both are bouncy energetic normal huskies anxiously waiting to be leashed. However this evening neither hardly reacted, and the one didn’t even move or lift his head. We called our vet and after some discussion and trying a couple things we ended up at the emergency vet, where we spend most of the rest of the night. A battery of tests and x rays, and such, yet nothing was conclusive We ruled out any possible poisoning and other hazards or injury. After about 24 -48 hours he was well. The only link is the trifexis. It may be that for some reason he is more sensitive to this particular drug than others. However, I have great concerns based on the reaction of both my dogs, and the one in particular. I hope my vet submits the results to the company for reference, even if an isolated case, these should be documented.

  36. Lisa says:

    My 5 mo German Rott had her first dose of Trifexis on Thursday, by they next morning she was vomiting, lethargic, refused food and water. We ended up at the ER vet by Sunday morning around 12:30 am with continued vomiting and bloody, mucus diarrhea. She had to be carried as she was too weak to walk. She was dispondant, and noticeably uncomfortable. The vet wanted $900 up front to begin a treatment plan. We did get something for nausea and vomiting with gave me a few hours to get Lola rehydrate… or try! I literally had to sit over her with bowl held to her mouth to get her to drink. She has still not eaten anything in almost 72 hrs now. We made it to our regular vet this am, Lola went from a beautiful 41 lb healthy girl to a weak, frail, 32 lbs and has lost all glow in her eyes. She looks so far away now that I wander if we can get her back! I am so angry that my dog was poisoned by the same hand that treats her. I know not every dog has the same adverse reaction to this medication, but obviously enough of our fur babies have suffered to realize there is a problem with this medication. I want my Lola back! I want my bouncy baby girl, who loved to run around and play and eat! I am just so sad seeing her so sick! We as animal owners trust the responsibility of caring for our dogs with our vets…. seems like until the vets take a stand and say this has to stop… other dogs are going to die due to this medication.

    1. joanne says:

      Lisa, that is so sad. I hope you have your baby back by now.

    2. Nancy says:

      Omg , how’s you poor puppy, ours is going in this morning , same symptoms!

  37. Laura says:

    We gave our 14 year old chocolate lab Trifexis for the first time last weekend after Sentinel became unavailable. We gave the pill with food that morning and by mid-afternoon, he was completely lethargic–would not lift his head, his eyes were rolled back and couldn’t focus and he was trembling. We physically got him up and he just stumbled around. We dropper-fed him some water and we started to see some improvement by late that night. The next morning, thankfully, he was back to his normal self. Needless to say, we will NEVER give him this medicine again and feel so bad we did that to him!

  38. Jody says:

    I gave trifexis for the first time to my 8 year old 11# pomeranian. She was fine for the first 36 hrs and then she started acting strange. She wouldn’t lay down, she just hid under the bed and wouldn’t come out to eat or go to the bathroom. When I did get her out it seemed like she couldn’t stand up very well and seemed to be shaking a bit. She also cried out when I petted her head. Very lethargic,but she never vomited (at least not that I know of) she will eat and drink water and she will go outside to pee and poo. But she is definately not the same dog. I’m wondering how long this will last? I’m not going to be giving her trifexis again or either one of my other poms. Where is the sentinel at?

  39. Milagros says:

    Hello, I witnessed the most horrific episode of convulsion/seizure on my Labrador Peggy. We started her on Trifexis about 2 weeks ago, the first day she was a little lethargic but the next day she was ok. But yesterday my dog was twitching, panting, twisting out control and felt on the floor as she has been stroke by lightning convulsioning as an epilepty would do. I have to say that she has been a healthy dog, no health problems at all and the only new thing on her diet is this medication, I took her to the vet today and she said not to give her the Trifexis anymore. She said that this medication can trigger epilepsy and can produce epilepsy in some dogs. However, she also said that it wasn’t enough evidence to support that, but not to give it to her anymore. Also, I need to say that I have a poodle that took the same medication as Peggy and she seems to be ok; however I was so scared yesterday that I am not giving this product to any of my dogs anymore. I don’t think is safe, the company should put seizure as part of the possible side effects….

  40. AmyJ says:

    My 5 year old mix (goldendoodle 90lbs) experienced vomiting the day after taking the Trifexis. He can take Comfortis and Interceptor, individually without any side effects. His appetite was also very low for a week after the Trifexis. It costs more but I buy the two pills and give them a few days apart. He does fine like that.

  41. Jessica says:

    My dog is an 18 month old Queensland Heeler mix. He has had really itchy skin, chronically itchy to the point where he itches so much he bleeds. I forgot to give him two doses of Trifexis, and he was seemingly better. I gave him Trifexis again, and his itching started up immediately. I’m not 100% that Trifexis is causing this reaction but I’m thinking of switching to a different medication to see for sure.

  42. Laurie says:

    I gave my 11 yr. old Lab Trifexis the first time on June 1. A couple of weeks later she developed a ‘mole’ on her snout. The 2nd dose was July 1. After looking at this mole for a few weeks I decided the Vet needed to see it. They did a biopsy and determined it was a mast cell tumor. We are now seeing an Onocolgist and getting treatment.

    She had been on Hartguard and Sentinel for years. Could there have been something in the Trifexis that triggered this? Have you heard of any other instances of something like this? I’m just trying to find out if there might be a possible connection.

    1. DrMarie says:

      Most likely this mast cell tumor is totally unrelated to Trifexis. I really can’t see how there could be a connection. Hope things work out ok for you!

  43. Tiffany says:

    I recently got back from my vet’s office because I went to question about Sentinel and why it was no longer being sold and I asked for what I should give my dog now and the vet tech suggested Trifexis. After reading all these reviews I am deciding to not even TRY my dog on this product. She is recently on Comfortis & Sentinel and hasn’t had any problems. (She’s a 50 lb. Lab/Boxer mix.) But now I only have one Sentinel pill left so I need something soon. I may just use Heartguard. I really am sorry to everyone on here who has had problems with this medication and I hope everyone’s dogs are doing okay!

  44. Debbie says:

    My 11 1/2 yr old Border Collie mix just had labs prior to some dental work. Her liver enzyme ALT has increased by more than 3x since being checked in March 2012 (due to being on Rimadyl for about a year). It is now way over normal. The only change is that three months ago – April 2012 – I started my dog on Trifexis. Has anyone heard of it affecting liver function? I have not noticed the specific issues noted here by many – but have been searching tonight for information about impact of this medicine on the liver.

    1. DrMarie says:

      I am guessing that this is unrelated to Trifexis but thank you for sharing.