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My dog has fleas even after Frontline Plus. What's the best treatment?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Large (61lb +) | Male | neutered | 1 year and 7 months old | 108 lbs

I treated my dog with frontline plus on the 26th (he did not have fleas I use it every month as a prevention) and on the 6th of the next month he had fleas! He is a 108 pound great Pyrenees/ German shepherd mix he is almost 2 he's never had fleas since I have had him. What do I do??!!

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1 Answer

Most Helpful Answer

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Answered By Lauren Jones VMD

Veterinarian

Published on June 13th, 2017

Oh no! Fleas are never a fun discovery! Unfortunately, I have seen many pets acquire fleas while on Frontline and my suspicion is that fleas are becoming resistant to Frontline. At this point, you can either switch Buddy to a different OTC topical preventative like K9 Advantix II or a prescription-based oral preventative like Nexgard or Bravecto. Some dogs can get tapeworms from eating infected fleas, so it is worth taking a stool sample to Buddy's vet for analysis. With the timeline of your dosing, it is fine to give a different flea preventative dose now. If you choose a topical preventative, be sure to avoid bathing Buddy for 2 days before or 2 days after the dose. Good luck! :-)

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