Is it normal for a dog to still be scratching after the first dose of flea medication?

Original Question: Hi. I am about to treat my 14lb Maltipoo with the second monthly application of Advantage 2 for fleas. Have not noticed much improvement after the first dose. Still a lot of scratching going on. Seems to be some confusion both online and in the product insert as to whether to apply it in one spot on the dog (between shoulder blades only), or in 3 different locations starting between shoulder blades ending at the base of the tail. I applied it in 3 spots for the first application and I'm wondering if this might have affected the efficacy of the product. She is due for her next monthly dose and I would like to find out before I apply it. Any advice would be appreciated. Thank you! -

Is it normal for a dog to still be scratching after the first dose of flea medication? Mar 5, 2018

Hi and thanks for submitting your question.

There is a simple answer. One dose of medication will help but it will not resolve the problem. To treat fleas effectively, you must disrupt the life cycle of the fleas by using multiple doses.

A dose of Advantage will kill the adult fleas on your pet, and it also has some activity on the larvae, which is the stage before they become adult fleas, but it does not kill the eggs in your home. There are vastly more eggs in your home than there are adult fleas on your dog. The first dose kills the adults, then the eggs in the environment grow up and jump on your dog, and then the second dose kills them. In fact, some people find more fleas about 2-3 weeks after using the first dose because there is a large wave of eggs that hatch and jump on your dog. The third dose should eliminate the fleas . So the quick answer is the first dose is useless without follow up doses. You must complete the prescription to kill the infestation on your dog.

As far as the application of the product, it will make no difference whether it is applied in 1 spot versus 3 different spots along the back. We often apply it in multiple spots just to be cautious. If your pet has a skin reaction to the medication, which is rare, the reaction may be small in each spot rather than an incredibly intense reaction in one spot. I would recommend you continue to apply in multiple spots along the back.

I hope this helps.

Dr. Clayton Greenway

Disclaimer: and its team of veterinarians and clinicians do not endorse any products, services, or recommended advice. All advice presented by our veterinarians, clinicians, tools, resources, etc is not meant to replace a regular physical exam and consultation with your primary veterinarian or other clinicians. We always encourage you to seek medical advice from your regular veterinarian.

Related Q&A

  • Why is my dog eating poop?
  • Answered by: Paul
  • Mar 9, 2023
  • Why is my dog licking so much?
  • Answered by: Paul
  • Mar 8, 2023
  • Why is my dog sneezing?
  • Answered by: Paul
  • Mar 7, 2023
  • Why is my dog drooling?
  • Answered by: Paul
  • Mar 6, 2023