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My puppy got too much Trifexis for her weight. What should I do?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Medium (23 - 60lb) | Female | unspayed | 2 months and 19 days old | 6 lbs

I may have given my puppy a dose of trifexis that was too large for her weight. We were given the do’s from the rescue assuming she met the 20 lbs limit but after giving it to her she seems to be acting slightly different. I’m worried that she isn’t quite the weight listed and I gave her too much. What should I do. I can’t get to the vet until the morning.

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on June 20th, 2018

So this medication contains a combination of Spinosad and Milbemycin. Milbemycin is used in dogs as a heartworm prevention, and can safely be given at two to four times the normal dose used for heartworm prevention. Spinosad is used for flea prevention, and it is a relatively safe drug. The most common side effects seen with its use include a decreased appetite, diarrhea, vomiting, and lethargy. Studies on research dogs showed no long term effects on dogs that were given ten times the recommended dose. More than likely, Molly will be just fine, but if you see any of the side effects that I mentioned above, have her seen by a vet just to be safe. Best of luck, I hope this helps!

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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.
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.
Updated on September 24th, 2025
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I have 110Lb. dog that takes trifexis and i gave him one of the pills without realizing he had already been given one 11 days ago. Will he be okay?
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.
Updated on September 24th, 2025
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My 35 pound dog (Rumor 6 years old Border Collie) MAY, not sure, have taken her Trifexis heartworm pill along with my 45 lbs dogs. I just don't know. I didn't see who ate it. This was yesterday. If anything was going to happen, when would I see s
Hi there. Trifexis has a very wide margin of safety (a dog could eat an entire box and not have any serious issues, in most cases), so it's unlikely that this will cause any problems. The most likely side effect would be vomiting or GI upset, in the first day or two after taking the meds. If she's acting normal so far, you probably won't see any issues at all. It's fine for her to continue with her normal daily routine as far as eating, exercising, etc.
Updated on September 24th, 2025
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Does trifexis make puppies sick ? My puppy has been gagging and her stock has been gurgling Since I’ve given it to her
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My dog ate 6 months worth of Trifexis that I accidentally left on the counter along with half a bag of all natural calming treats. He must have eaten then when I left for work this morning at 6 am. He threw up 5 or 6 times. I just got home from work
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Updated on September 24th, 2025
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I just gave Sophie her Trifexis and even though she is now 7 months, she still has the same side effects from the pill. Lethargy, upset stomach, and general feeling miserable. She had worm issues when she was a few months younger and dont want that t
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Updated on September 24th, 2025
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My miniature golden doodle (9 months old) had a dosenof Trifexis today. 2 hours later she vomited, and is now very lethargic. Is there anything I can do to help her?
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Updated on September 24th, 2025
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My 6 month old cavapoo has been taking Trifexis since she was 3 months old without any reaction. She was spayed on August 2nd and weighed 9.8 lbs. I purchased the tablet at that time. This one was for 10-20 lbs which is the next one up from the pink
Thank you for submitting your question regarding Fiona. She is unlikely vomiting from the Trifexis if she hasn't in the past. That is a small dose change for her. There are numerous causes of vomiting such as dietary indiscretion, an infection, stress or something more serious such as eating a foreign object. If she still refuses to eat or cannot keep food or water down, then she will need to see a veterinarian today. Being such a small breed dog, it is easy for her to become dehydrated. If she seems to be feeling better, give her small frequent amounts of water and food throughout the day today. I hope this information helps!
Updated on September 24th, 2025
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I gave my 8 month old puppy trifexis for 1st Time this morning with a couple pieces of hot dog. came home this evening he threw up about 5 times. Not lethargic but very tired
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Updated on September 24th, 2025
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My dog has dirrarea after few hours of consuming Trifexis what should I do?
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