PetMeds® Frontline Plus Questions

Some of the more common recent questions I’ve received in the clinic regarding f and its use for flea and tick prevention in pets. A big concern I often receive is the quality of Frontline Plus being carried by online pharmacies like 1800petmeds and whether it is the same as those used and sold by veterinary offices. The truth of the matter is that Frontline Plus is a prepackaged product by Merial, and is the exact same one carried by 1-800-PetMeds as your local veterinarian. Improper application is one of the most common reasons for flea treatment failure

Another common question is, “Why does my pet still have fleas after applying Frontline?” (after a few consecutive months. The most common reasons for flea treatments failing is typically because of improper application, or more commonly failure to treat the environment of the pet, including the home and yard; where 80% of the flea life cycle occurs. Along the same line, some products, however will work better on some pets than others. So, if there are still fleas even after properly treating the home and using Frontline Plus for several months, I would suggest having your house professionally treated by an exterminator and/or change to a different product such as Advantage.

If a pet still has fleas, many veterinarians will use the product more frequently than once monthly, sometimes as often as once every 2-3 weeks. However, this process is often considered to be “off label use,” and I would not use the product this way unless first speaking with your pet’s veterinarian. If a client is currently using a different topical such as Revolution or Advantage, it is safe to change to Frontline Plus after 3-4 weeks from the date of last application of the other product. While Frontline Plus is labeled as waterproof, I usually advise clients to wait at least 24 to 48 hours before bathing their pet. Side effects to Frontline Plus are rare but may include hair loss/skin irritation at site of application, (rarely) digestive upset, (and even rarer) immunological reactions of the blood or neurological reactions like seizures. Again, these are very rare, as most pets tolerate this product quite well.

Related Posts


  1. Would I be able to give him the rest of the dose today?

  2. HI Rachael. I usually dont suggest redosing the front line, even at lower dose, for at least 2 weeks after the initial dose. In future, it may be best to consider an oral prescription medication for fleas if you need additional coverage; i.e such as oral comfortis, etc from 1800petmeds.

  3. I applyed my nine-month-old cat frontline plus The day after Christmas and he hasn’t been the same since he eats and drinks but all he wanted to do was sleep he hasn’t played in probably four days now what is going on?

  4. Hi Gina and thank you for your question. If you haven’t already, we recommend you consult your veterinarian. However, for non-emergency questions, you can contact Dr. Dym directly using our Ask the Vet form. I hope your kitten is feeling better soon!
    ~ Abby, PetMeds Pro

  5. I need help… I’ve done everything I treat my cats with Frontline plus and they’re still coming back from being outside covered in ticks nymphs, all around their eyes and ears where there’s not a lot of hair. I take tweezers every single night and pick as many as I can off them and eyes are swollen they look uncomfortable and they really don’t like me picking them with tweezers every night, I’m sure it hurts what else can I do these ticks are going to kill us literally my husband and I both have Lyme disease which we had gotten in The Last 5 Years when we moved out to Mount Desert Island and I have never seen anything like this in my life they literally are everywhere all the time

  6. Hi Stephanie. I’m so sorry you’re having trouble with ticks; this can be a difficult problem and usually requires a multi-prong approach including treating your yard and home. We do always recommend you discuss this with your veterinarian. However, for non-emergency questions, you can contact Dr. Dym directly using our Ask the Vet form. We hope you’re able to resolve the situation quickly!
    ~ Abby, PetMeds Pro

  7. I applied my dogs monthly dose while it was a little dark and she moved when I put it on.. I noticed that the applicator was pretty dry so im guessing its possible I had a bad dose and there was no medicine in this applicator.. Im afraid to put another dose on her but I dont smell it on her and I dont see the “wet fur” after.. I would like to put another dose on but worried that either she got a little bit or none and I hate to take her up north when i am not to sure anything got on her.. Can I do another dose?

  8. Hi Nicole! For any medical concerns, we always recommend you consult your veterinarian. However, for non-emergency questions, you can contact Dr. Dym directly using our Ask the Vet form.
    ~ Abby, PetMeds Pro

  9. I put flea and tick solution on my cat,i didn’t realize I did it 24 days ago,i did it 6 days early,will this harm my cat

  10. I applied frontline plus on my cat 48 hours ago and he still has live fleas. Why isn’t Frontline working?

  11. Hi Debbie and thanks for your inquiry! There are a number of factors to consider should it appear that your pet’s flea control is not working. This article may be of help:
    ~ Abby, PetMeds Pro

  12. My dog’s frontline treatment is due the 24th. I’m having family over for Christmas holidays. Can y delay her treatment so family members don’t get the medication on them and she can be petted by everyone?

  13. Hi Mary. If you are not seeing evidence of a flea infestation, a one-day delay in application should not have any adverse effects. Happy holidays!
    ~ Abby, PetMeds Pro

  14. My cat recently caught fleas so we used the frontline spot on solution. It seemed to be working well and the fleas were dying. However it’s now been just over 2 weeks and have notice that because we used the regular frontline instead of plus it’s not effecting the younger fleas. Would it be safe to apply frontline plus now or should I wait till it’s been a month.

  15. Hi Emma. The manufacturer recommends you do not apply before the month is over. However, for immediate flea relief, you can administer a dose of Capstar which works within 30 minutes (but the effect lasts just 24 hours).
    ~ Abby, PetMeds Pro

  16. How long do I have to wait between switching from Frontline to Comfortis?

  17. Hi Jo. We recommend consulting with your veterinarian, or feel free to speak with one of our pharmacists at 1-888-738-6331.
    ~ Abby, PetMeds Pro

  18. I put frontline plus on all three of my cats a week ago. I washed all of there bedding and treated the furniture, washed my bedding and the curtains. . I have no carpet and my cats do not go outside ever. So why do my cats still have fleas. My calico is pulling her the hair out and leaving bloody marks on her neck and lower back near her tail. This is the first time I have ever used this product. Can I really it after only 7 days??

  19. Pingback: How Long Does it Take Frontline to Dry? - Feline Follower

  20. Hi Sarah. We’re sorry that Frontline Plus is not working well for your cats! Here’s an article from Dr. Dym that might be of help: If you ordered from us, please don’t hesitate to contact us to take advantage of our unconditional product guarantee. You can reach us at Thank you.
    ~ Abby, PetMeds Pro

Leave a Comment