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Trifexis side effects

Species: Dog
Breed: Shetland Sheepdog
Age: 8-11 years
I just read your article about Trifexis and was very disturbed. We have three Shetland Sheepdogs, ages 4.5 yr, 9 yr, and 10.5 yr., all normal/normal for the MDR1 gene mutation. All three dogs were very ill after their first dose of Trifexis approx.12 hours later. Would not eat, severe abdominal pain. The youngest started to recover 36 hours later and was apparently ok after a week. The oldest took almost a month to completely recover. The 9 yr. old was in emergency 24 hours after the dose but never was 100% afterwards and eventually died from liver damage, gall bladder damage, and bile duct damage. All three cases were reported to Elantro, The one who died is also in the U of Texas data base and AKC-CHF as the only recorded case of bile duct cancer in the United States.
In your article you asked people to report problems to you. I wanted to do so. My only questions are
(1) Have you gotten other reports like mine? If so, how many, etc?
(2) The label needs to have a lot more warnings on it. Vets still seem to be recommending it. What can I do to prevent other cases like mine?


Online vet, Dr. Marie

Dr. Marie replied:

Thank you for sharing your story.

I belong to something called "Veterinary Information Network" where vets speak with other vets about things that are happening in our profession. There is the odd case where it is mentioned that a dog had some sort of reaction to Trifexis, but it is not common. The most common complaint is mild vomiting within a few hours of receiving the medication. There are some dogs that can get a strange neurological reaction where they daze off into space but this seems to be quite rare according to the reports that I am hearing from other vets.

The symptoms that you are describing sound quite severe. The fact that they happened 12 hours after having Trifexis are indeed concerning. It is good that these were reported to the drug company.

I have alerted the FDA to the many comments that were left on my article on Trifexis side effects. The vets in the Veterinary Information Network have discussed my article as well. If there really is a danger with this drug, then the FDA really should step in soon.

Thank you very much for sharing.

Dr. Marie.


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Disclaimer: Although Dr. Marie is a qualified veterinarian, the information found on this site is not meant to replace the advice of your own veterinarian. AskAVetQuestion.com and Dr. Marie do not accept any responsibility for any loss, damage, injury, death, or disease which may arise from reliance on information contained on this site. Do not use information found on this site for diagnosing or treating your pet. Anything you read here is for information only.

Customer reply:

Thank-you for your kind response. Yes, the symptoms were both unexpected and quite severe. If it had not happened to all three dogs, I might be looking at other causes. Since we had used the molabedium oxamine for years, the problem had to be the spinosad or the combination. I have no information from Elantro that this batch was contaminated in any way, but they did say that they were getting a 2% fatality rate. Please caution others to use some drug that has been on the market for years.

No reply expected. Thank-you again.


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Dr. MarieDr. Marie is a veterinarian who practices in a busy animal hospital in Ottawa, Ontario. She created Ask A Vet Question as a resource for good, accurate veterinary advice online. Dr. Marie treats dogs, cats, hamsters, guinea pigs, and rats. She has been a vet since 1999.

Is an online vet visit just as good as a trip to your veterinarian? No! But, many times, asking an online veterinarian a question can help save you money. While Dr. Marie can't officially diagnose your pet or prescribe medications, she can often advise you on whether a vet visit is necessary. You can also ask Dr. Marie for a second opinion on your pet's condition.