My dog accidentally got a double dose of Trifexis. Is she safe?
Updated On September 23rd, 2025
My dog was given her trifexis yesterday, but then my roommate didn’t know I gave it to her and he gave her another dose today. Will she be ok? She is a 72 lb GSD.
2 Answers
Most Helpful Answer
Published on November 17th, 2019
This medication contains a combination of Spinosad and Milbemycin. Milbemycin can be used safely in dogs for heartworm prevention but has other uses as well, and can be given at a dose two to four times the normal dose that we use for heartworm prevention, so I would not worry at all about a higher then normal dose of that medication. Spinosad is used for flea prevention and is a relatively safe drug. The most common side effects seen with its use include a decreased appetite, vomiting, diarrhea, lethargy and rarely, in dogs with a low seizure threshold, possible seizures. Studies on research dogs showed no long term effects on dogs that were given TEN times the recommended dose. Side effects that were seen at that high dose included nausea, vomiting, a decrease in appetite and some diarrhea. She will probably be OK but all you can do at this stage is monitor her for any signs of toxicity. If any are noticed she needs to see a vet immediately.
17Pet Parents found this answer helpful
Related Answers from Veterinarians
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Published on September 24th, 2017
Generally the toxic dose for spinosad is 500mf/if when we start to see side effects. The dose that this would have gotten would have been about 3240mg. The toxic dose would be 25,000mg for a dog Thor's size. What this means is that there shouldn't be any life threatening problems here and it should be safe to monitor for now. Here are some things that would make me recommend going to the vet: 1. Lethargy and lack of appetite 2. Tremors or seizures 3. Vomiting for more than 12 hours I hope this helps! Please let me know if you have any other questions or concerns. I am also available via consultation if needed.
1Pet Parents found this answer helpful
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