Petco Text Logo
Petco Pet Logo

  • Two Easy Ways to Start Earning Rewards!

Why does my dog still have fleas after using Capstar and Frontline?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Small (up to 22lb) | Male | unneutered | 8 years and 6 months old | 12 lbs

I spoke with someone there but I think off the record. It was recommended I give Boogie Capstar for his flea infestation and then start his Frontline which I did yesterday. The Capstar didn't work all that well and now on second day, I can just lean over and look at Boogie's hair and see fleas all over. Does Frontline get stronger as the month goes by by any chance? Boogie is miserable and I don't know how to help.

2 Answers

Most Helpful Answer

Image profile

Answered By Stacey Anstaett, DVM

Veterinarian

Published on July 23rd, 2018

I'm so sorry you are having a hard time with Boogie! Capstar is safe to give daily, but ONLY kills adult fleas. More fleas will be jumping onto Boogie daily until all of the viable eggs in the environment have hatched or been rid of. Frontline (and Advantage and Revolution) kills adult fleas AND makes the eggs laid by the fleas that are on the dog unable to hatch once they are in the environment. That's why it takes some time to see results, whether you are using Frontline, Advantage or Revolution. That is also why Capstar continues to be beneficial in killing the adults that are on the dog. Think of it this way. Adults fleas get onto the dog. They eat, mate, poop, and lay eggs. The poop from the fleas, and the eggs, both drop off into the environment. When the eggs hatch out, which takes 2 weeks, the larvae (baby fleas) feed on the flea poop that was dropped into the environment. They ultimately develop into the adult fleas that will again find an adult host to infect. Since an adult flea can lay 50 eggs a day, you can see how important it is to treat the environment and break the life cycle. You may find this article helpful. http://www.petsandparasites.org/dog-owners/fleas/ To specifically answer your question, Frontline doesn't "get stronger" with time, but it takes consistent treatment to break the cycle of new fleas hatching out in the environment and getting back on. Until you've got better control, apply either Frontline (or Advantage, or Revolution) as frequently as recommended by your vet; typically this will be about 2 week intervals for 4-8 weeks. Again, consult with your vet for specific advice on your individual dog's needs. Also, vacuum and wash bedding, carpets, couches, etc. I hope that clarifies things for you a bit. Don't hesitate to post on the forum again or request a consultation for further assistance. Thanks for asking PetCoach!

Vote icon

1Pet Parents found this answer helpful

Other Answers

  • Image profile

    Answered By Dr. Melanie, BVSc MS

    Veterinarian

    Published on

    It's safe to give Boogie another Capstar now, which should help with the fleas. You can give it a couple of days in a row safely. It's also very important to disinfect the environment, as that will be a continuing source of fleas. Wash his bedding in hot soapy water, and vacuum the furniture and carpet surfaces. You can use a spray to kill fleas in the house, such as Indorex, or a flea bomb would work well to kill the fleas in the home. As for the Frontline, I have seen some resistance to fleas with it, but it's not safe to give another topical flea medication just yet. I'd wait two weeks, and then apply Advantage or Revolution. You can give Capstar daily during this time to kill the fleas, and be sure to disinfect the home. I hope this helps!

    Vote icon

    0Pet Parents found this answer helpful

See More Answers

Related Questions

Petco Pet Education Center
Health & Wellbeing
What fish dog food helps dry skin if my dog eats Science Diet?
Is your dog's dry skin a concern? A certified vet offers expert advice on finding the best fish-based dog food alternatives to Science Diet for essential oils.
Updated on February 04, 2026
Petco Pet Education Center
Health & Wellbeing
My degu has a white bump in its fur. Should I take my pet to the vet?
Worried about your pet degu's white pustule? A certified vet discusses this potential skin infection, explains why not to pop it, and guides your next steps.
Updated on December 04, 2025
Petco Pet Education Center
Health & Wellbeing
My pet's ear mite treatment isn't working. What else could it be?
Pet still itching after treatment? A Petco vet clarifies it may not be ear mites. Discover effective solutions like Revolution or consulting an exotic vet.
Updated on December 04, 2025
Petco Pet Education Center
Health & Wellbeing
My rat is losing weight and has breathing issues. What should I do?
Dambo's weight loss, rough breathing, and mucus worry you? A Petco veterinarian addresses these concerning symptoms and recommends urgent professional care.
Updated on December 04, 2025
Petco Pet Education Center
Health & Wellbeing
My pet has worsening sores and scratches. Could it be an infection?
Nike's worsening sores and constant scratching worry his owner. A certified Petco veterinarian offers expert guidance on potential causes like bacterial infections and next steps.
Updated on December 04, 2025
Petco Pet Education Center
Health & Wellbeing
My dog's matted fur bled after cutting. Should I take him to the vet?
Did your pet bleed after matted fur removal? A trusted vet explains potential infection, wound care, and why immediate veterinary attention is crucial for healing.
Updated on December 04, 2025
image
Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Book Now

Sponsored