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K9 Advantix II Flea & Tick Treatment for Large Dogs 21-55 lbs

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6 treatments
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K9 Advantix II Flea Treatment for Dogs offers broad spectrum flea control and protection against ticks and mosquitoes, too. It is specifically formulated for dogs and comes in a convenient, monthly topical application that not only kills but also repels fleas, ticks and mosquitoes. K9 Advantix II also kills all life stages of fleas, repels biting flies and kills lice. It contains imidacloprid, permethrin and pyriproxyfen that work in concert to repel and kill parasites that can potentially transmit disease-causing organisms. K9 Advantix II is a flea treatment for use on dogs 7 weeks and older. Do not use K9 Advantix II on cats.

Key Benefits

  • Specifically formulated for dogs and comes in a convenient, monthly topical application that not only kills but also repels fleas, ticks and mosquitoes
  • Repels and kills ticks of all types including Deer ticks, American dog ticks, Brown dog ticks and Lone Star ticks
  • Prevents fleas on treated dogs from infesting your home
  • Kills fleas on dogs within 12 hours and continues to prevent infestations for a month
  • Contains imidacloprid, permethrin and pyriproxyfen which work to repel and kill parasites that can potentially transmit disease-causing organisms


Use only on dogs and puppies 7 weeks of age and older and weighing 21 to 55 pounds. DO NOT USE ON CATS. Keep out of reach of children. Do not get this product in dog's eyes or mouth. As with any product, consult your veterinarian before using this product on debilitated, aged, pregnant or nursing animals. Individual sensitivities, while rate, may occur after using ANY pesticide product on dogs. If signs persist, or become severe, consult a veterinarian immediately. If your animal is on medication, consult your veterinarian before using this or any other product.

Active Ingredients

  • Imidacloprid 8.80%
  • Permethrin 44.00%
  • Pyriproxyfen 0.44%

See all items by K9 Advantix II

  • Item Number
  • Brand
  • Breed Size
  • Lifestage
    Puppy, Adult


How to open:

  • Be sure tube is at bottom of pouch.
  • Using scissors, cut the pouch across the top and remove tube.

How to apply:

  • Use only on dogs.
  • Remove applicator tube from the package. Use scissors and peel down foil.
  • Hold applicator tube in an upright position. Pull cap off tube.
  • Turn the cap around and place other end of cap back on tube.
  • Twist cap to break seal, then remove cap from tube.
  • The dog should be standing for easy application. The entire contents of the K9 Advantix II tube should be applied evenly on the top of the back from the shoulder to the base of the tail. At each spot, part the hair until the skin is visible. Place the tip of the tube on the skin and gently squeeze to expel a portion of the solution on the skin. Do not apply an excessive amount of solution at any one spot that could cause some of the solution to run off the side of the dog.
  • Discard empty tube.
  • In cases of severe pest infestations, retreatment is allowable earlier than 4 weeks. Do not retreat more often than once every 7 days. After pest control is attained, return to a monthly retreatment schedule.

Frequently Asked Questions

How is K9 Advantix II different from K9 Advantix?

With the addition of an insect growth regulator (IGR), K9 Advantix II kills all life stages of fleas. K9 Advantix II also prevents development of fleas, flea eggs, larvae (maggots), and pupae (cocoons), and prevents fleas on a treated dog from infesting your home.

What is the benefit of repellency?

Repellency helps prevent ticks, fleas, and mosquitoes from attaching, biting or feeding. A repelled parasite doesn’t bite or attach. If it doesn’t bite or attach, it can’t transmit the organisms that may cause disease.

What is the difference between K9 Advantix II and other tick and flea products?

K9 Advantix II repels and kills ticks, fleas, and mosquitoes. It repels biting flies and kills lice, too. Its repellency activity and broad spectrum make K9 Advantix II different from other tick and flea products.

Is K9 Advantix II waterproof?

Yes. There is no need to reapply the product after weekly swimming or a bath. For best results, use a non-detergent shampoo.

Can I use K9 Advantix II on my cat?

No. K9 Advantix II must not be used on cats because of a cat’s unique physiology and inability to metabolize certain compounds.


Dog Weight K9 Advantix II Volume
10 pounds and under Small Dog 0.4 mL tube
11 to 20 pounds Medium Dog 1.0 mL tube
21 to 55 pounds Large Dog 2.5 mL tube
over 55 pounds Extra Large Dog 4.0 mL tube

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Customer Reviews

K9 Advantix II Flea & Tick Treatment for Large Dogs 21-55 lbs is rated 4.7 out of 5 by 363.
Rated 1 out of 5 by from Did not work for my lab mix We used frontline before and had no problems just occasionally my dog would have ticks on him but not latched, switched to k9advantix with their promise to also repel ticks. Our house backs up to the reservoir which we are in a lot hunting, hiking, etc. After only one dose of k9advantix, I found 3 biting ticks on my dog in the same week. Switching back to frontline immediately. Chewy customer service was great - will continue to buy pet supplies from them
Date published: 2017-02-25
Rated 5 out of 5 by from Looks like its working I am two weeks into using this product and so far it's as advertised. I have a new 16 mo. old puppy whom I've had a month. I live in the woods in tick country in SW Florida and my wife and I get ticks much less the dog. We decided to be proactive when we started finding a few ticks on the dog. Since application on the pup we've found no live ticks or fleas at all. Good product.
Date published: 2017-01-29
Rated 5 out of 5 by from This product did exactly what it promised to do. My dogs had a serious flea problem. After using this product, the fleas are gone. Both my dogs had a serious flea problem. I tried flea shampoo, natural flea repellant, nothing was working. I used this product in the past when I purchased it through my Vet, who no longer carries it. It's great to know I can order it through Chewy. It works great. Fleas are gone!
Date published: 2017-02-23
Rated 5 out of 5 by from K9 Advantix II works the best! I have been using K9 Advantix II for 13 years on my dogs and will continue to use, for no fleas, no ticks plus it is waterprooof. My dogs can get in the creek the same day it is applied, so no worries if your dogs swim on a daily basis, this brand holds up!
Date published: 2017-02-09
Rated 5 out of 5 by from Does the job I have been using K9 Advantix II for several years. I live in a wooded area and take my dog for walks in the woods every week, all 4 seasons. I rarely find a tick and when I do it is near death. in addition, it's easy to apply.
Date published: 2017-01-17
Rated 5 out of 5 by from This is the only brand I have had success with I have tried more affordable products. Being retired that's always a consideration for me. But, more important is results. Advantix works. I love my dog and it is very important to me that he is flea free. Thanks.
Date published: 2017-03-03
Rated 5 out of 5 by from Great price, great service, great delivery I ordered from Chewy because their prices are more than competitive and their service and speed of delivery are excellent. Highly recommend shopping with Chewy.
Date published: 2017-03-10
Rated 5 out of 5 by from Very effective! We have been using this product for over 9 years on our 3 dogs, 2 labs and a puggle, and have had no flea issues at all. We highly recommend it.
Date published: 2017-01-24
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