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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

Dr. Melanie, BVSc MS

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!
Vote Icon1Pet Parents found this answer helpful

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