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Is it safe to cut dog flea medication if I bought the wrong size?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Female | spayed | 3 years and 7 months old | 15 lbs

I accidentally bought the incorrect size flea treatment for my dog. She is 7kgs and I bought the medium comfortis plus (560 mg spinosad and 9.3 mg milbemycin oxime) which is for dogs with weights of 9.1-18kg. I should have bought the small one (270 mg spinosad and 4.5 mg milbemycin oxime) for weights of 4.6-9kg. Do you think I can just cut the medium ones in half and give them to her or do I need to get the small sized ones?

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on January 25th, 2018

Definitely get PYY the smaller size. It's never recommended to try to cut a larger dose of the medication in half because you could either under dose your dog, or accidentally overdose them. I hope this helps!

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