On Sale

K9 Advantix II Flea & Tick Treatment for Medium Dogs 11-20 lbs

  • List Price:


  • Price:

    $65.99 FREE 1-2 Day Shipping on this item

  • You Save:

    $27.00 (29%)

In stock
6 treatments
  • 2 treatments
  • 4 treatments
  • 6 treatments
- Quantity +


Help protect your precious pooch from parasitic pests and the potentially harmful diseases they can transmit with K9 Advantix II Flea & Tick Treatment for Medium Dogs. This broad-spectrum, veterinarian-recommended treatment is specifically formulated to repel and kill fleas, ticks and mosquitoes on contact with no painful biting required. It further kills all life stages of fleas to prevent re-infestation, and even kills lice while also repelling biting flies. The waterproof formula for puppies and dogs 7 weeks or older and weighing between 11 and 20 pounds continues working for up to four weeks, even after bathing or swimming.

Key Benefits

  • Broad-spectrum, veterinarian-recommended treatment repels and kills fleas, ticks and mosquitoes on dogs 7 weeks or older and weighing 11-20 pounds.
  • Begins working within 12 hours and kills pests on contact with no painful biting required.
  • Kills all life stages of fleas to prevent re-infestation; also kills lice and even repels biting flies.
  • Waterproof formula continues working for up to four weeks, even after bathing or swimming.
  • Convenient, monthly topical application contains imidacloprid, permethrin and pyriproxyfen; available in packs of 2, 4 or 6 treatments.


USE ONLY ON DOGS AND PUPPIES 7 WEEKS OF AGE AND OLDER AND WEIGHING 11 - 20 LBS. DO NOT USE ON CATS. 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. Keep out of reach of children.

Active Ingredients

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

See all items by K9 Advantix II

  • Item Number
  • Brand
  • Breed Size
    Small Breeds
  • Lifestage
    Adult, All Stages


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.

  1. K9 Advantix II Use & Care Instructions


Dog Weight K9 Advantix II Volume
Under 10 lbs Small Dog 0.4 mL tube
11 - 20 lbs Medium Dog 1.0 mL tube
21 - 55 lbs Large Dog 2.5 mL tube
Over 55 lbs Extra Large Dog 4.0 mL tube

Pet Lovers Also Bought

Customer Reviews

413 reviews 413 Reviews 4.6 out of 5 Stars

93% Recommend

93% of reviewersrecommend this product

4.6 / 5

You've Already Reviewed This Item

Showing 1-10 of 413 Reviews

Sort by:
Filter by:
  • Simply the best!

    By on Top 100 Contributor

    I've used this treatment for many years on both of my dogs. It's the absolute best at getting rid of fleas. It's not 100%. It tends to last a little longer than 3 weeks. I can always tell when the 30 days are up because they can get a few fleas, but compared to other treatments I've used, this is by far the best. I've seen fleas on my dogs with other treatments after a week! But this one lasts the longest. I will continue to buy this for my little ladies.

    You liked it! Something went wrong. Please try again later. Report
  • Works fast

    By on

    My 13 pound long hair chihuahua recently had a run in with a few fleas and as it turns out is allergic to flea bites. He was itching uncontrollably so I ordered the k9 advantix II and in 2 days I got my package and applied the medication as directed. This stuff worked fast at killing the adult fleas which was great and is now preventing any new fleas. Very happy with this product.

    You liked it! Something went wrong. Please try again later. Report
  • May be working maybe not

    By on

    Started out with Advantage. After 4 separate applications of Advantage, I switched to Advantix II to try to get rid of fleas. Have given one dosing of Advantix II. She still has fleas but appears to have less. Since it takes 3 months for the flea cycle to complete, I need to wait one more month before I switch to something else if the fleas aren't gone. Therefore, I can't give a recommendation for Advantix II at this time.

    You liked it! Something went wrong. Please try again later. Report
  • great product

    By on

    If you are looking for a great quality flea and tick product for your canine pal, I absolutely recommend this one!! I've been using it for over 12 years without any issues and I live in southern Florida!! I have tried other brands that claim they are "just as good" for less money but then I would find a tick or fleas on my pets. Many times my veternarian has recommended the "latest and greatest" pill or whatever that has came out for our pets, but I never will switch. Many times I find out later about horrible things happening to some of those pets with these "latest and "greatest" products. I will never change and will only ever buy this product!!

    You liked it! Something went wrong. Please try again later. Report
  • K9 Advantix for medium dogs 11-20 lbs

    By on

    I administer the treatment each monthly on my little buddy and I also treat my carpeted areas and his bedding as well but he still scratches sometimes as if he still has fleas. I bath him with a quality flea bath product every two weeks and during summer months sometimes weekly. So I'm scratching my head on why he would still have fleas.

    You liked it! Something went wrong. Please try again later. Report
  • K9 advantix II - Vet Recommendation

    By on

    Our pet has had only one dose, and that said I believe it is too early to tell if this is the best solution. However, our Veternarian recommended this product over other like products and we do trust her judgement.

    You liked it! Something went wrong. Please try again later. Report
  • K9 Advantix II is the best!

    By on

    This is the best product on the market to give your dog full protection. It not only kills fleas and ticks, but also repels them and mosquitoes. This is a great aid in the prevention of heart worms caused by mosquitoes. For years I've been treating my dogs against fleas and ticks and the terrible diseases they cause. Its great to have another line of defense against mosquitoes. This is the best product, great price, and fast shipping. Totally satisfied.

    You liked it! Something went wrong. Please try again later. Report
  • It Really Works!

    By on

    We have never had problems with fleas on our dogs until this year. This year has been awful! Our groomer recommended K9 advantix II for our medium dog and two large dogs. Within two days we could tell a difference in the amount of chewing and scratching with all three dogs. It has really helped make them more comfortable and kept the fleas to a minimum.

    You liked it! Something went wrong. Please try again later. Report
  • Best Flea & Tick Product

    By on

    Best Product -been using on all my dogs for quite a while. Others tried did not work as well. Live around plenty of shrubs, trees and overgrowth, ticks especially near our walk areas are abundant. Best Price is Chewy saved a good bit on both dogs. Better yet free shipping.

    You liked it! Something went wrong. Please try again later. Report
  • Have Never Had Any Issues

    By on

    I've used this flea and tick product on my dog since adopting her a few years back and I've never seen a tick or flea on her even though she spends A LOT of time around other dogs and outdoors at the dog park. She has wiry hair so there has never been any problems with oiliness either. Overall great stuff and Chewy is the lowest price I can find!

    You liked it! Something went wrong. Please try again later. Report