K9 Advantix Flea, Tick & Mosquito Prevention for X-Large Dogs, Over 55 lbs+, 2-Monthly Treatments

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About This Item

Details

  • K9 Advantix for extra large dogs is ideal for dogs ages seven weeks and older weighing over 55 pounds.
  • Formulated to protect your pup from fleas, ticks, mosquitoes, biting flies, and lice for 30 days per treatment.
  • Works on contact to kill and repel fleas on dogs within 12 hours of application even without a bite.
  • This easy-to-apply topical treatment is fragrance-free and waterproof after 24 hours.
  • K9 Advantix offers fast relief—no prescription needed.

Ingredient Information

Instructions

K9 Advantix for Dogs

K9 Advantix, from the Advantage brand, prevents and treats fleas, ticks, mosquitoes, biting flies, and lice on dogs. It works through contact to kill fleas on dogs within 12 hours of initial application. Do not use on cats.

One Application Protects for 30 Days

This once-a-month topical flea and tick treatment is easy to apply, and the fragrance-free formula is waterproof after 24 hours of application. Plus, K9 Advantix is available without a prescription, so you don’t have to go to the vet to get it.

How It Works

K9 Advantix kills fleas through contact. It also kills and repels mosquitos and ticks, kills lice, and repels biting flies. Apply K9 Advantix to your dog once every 30 days according to the complete directions for use on the product label.

Find the Right Dose for Your Dog 

Your dog should be at least 7 weeks old to use K9 Advantix. It comes in four sizes, according to your dog's weight: Small Dog (4-10 lbs.), Medium Dog (11-20 lbs.), Large Dog (21-55 lbs.), and Extra-Large Dog (over 55 lbs.). Use as directed by label.

About Advantage

The Advantage family of products has what you need for a complete flea treatment and prevention plan, including monthly topical treatments, pet shampoos and sprays, household sprays for carpets and crevices, and even a yard and premise spray.

Shop Advantage

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Reviews
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4.4
Rated 4.4 out of 5 stars
499 Ratings
Terms & Conditions

Customers Mention

Chewy identifies key considerations with the help of artificial intelligence and our veterinarians.

Ease of Use

79% Positive

Effectiveness

80% Positive

Ingredients

77% Positive

Long-Term Benefits

80% Positive

135 Customer Reviews

Always consult a veterinarian about your pet’s health needs. Customer reviews should not be used as medical advice.

Rated 5 out of 5 stars
By Al on Jan 12, 2026

Quick turnaround

I was amazed at how quickly you turned this request into product at my door. I only asked you to move up the automatic shipment yesterday and I have my dog food

I was amazed at how quickly you turned this request into product at my door. I only asked you to move up the automatic shipment yesterday and I have my dog food today. I appreciate that.

Rated 5 out of 5 stars
By Kristina on Oct 16, 2025

Works when you’re consistent.

I have a big group of dogs of all sizes and breeds a few have really bad flea dermatitis if they have even one bite them and scratch until they have patches of fur

I have a big group of dogs of all sizes and breeds a few have really bad flea dermatitis if they have even one bite them and scratch until they have patches of fur missing. Some can take the expensive chewable tablets every month, some have heath conditions that require them to take the topical treatments. Hadn’t had a problem with fleas in years since we had a stray cat overpopulation issue. I had to bomb their sleeping area with Diatomaceous Earth and flea bath everyone and applied these when they were fully dry. I know there are still fleas in the area because neighbors complain about it with their dogs but I haven’t had any issues since I started using K9 Advantix every month for all of my dogs. It’s inexpensive and doesn’t leave an oily film on their fur like some other topical treatments. After the second month dose we saw no more fleas on them or the house. No more scratching or biting or missing fur. I recommend it to anyone who needs it.

Rated 5 out of 5 stars
By Penny on Jan 15, 2026

Buster

We live in the country surrounded by woods. Gotta keep the fleas and ticks off. I’ve been using this medication for a few years. It works really well.

We live in the country surrounded by woods. Gotta keep the fleas and ticks off. I’ve been using this medication for a few years. It works really well.

Rated 4 out of 5 stars
By Phillip on Dec 1, 2025

It works to repel mosquitoes, flies and ticks.

I love the fact that these prevent mosquitos, flies and ticks. I swear by this brand. Was paying twice the cost for the K9 Advantix v2 and for the price, these worked

I love the fact that these prevent mosquitos, flies and ticks. I swear by this brand. Was paying twice the cost for the K9 Advantix v2 and for the price, these worked the same. Found no 'critters' in my bed or under my pjs.

Rated 5 out of 5 stars
By Dana on Oct 17, 2025

Customer service

All the items were exactly what I ordered, and they came in a short time . I called Dr. Duke and my vets office since that what I ordered is perfect. They write

All the items were exactly what I ordered, and they came in a short time . I called Dr. Duke and my vets office since that what I ordered is perfect. They write ingredients needed actually the main ingredient for heartworm prevention medication is.Overheard .

Rated 5 out of 5 stars
By Christina on Sep 9, 2025

Inexpensive

I have a 100+# dog, a Great Pyrenees. A family member stayed temporarily with us and their dog had fleas with no treatment plan. The house was infested within a

I have a 100+# dog, a Great Pyrenees. A family member stayed temporarily with us and their dog had fleas with no treatment plan. The house was infested within a week, I swear. Frontline Plus was the treatment we could all afford for our pets. Because we were infested, I understand it can take 3 or more months to get control of the little nasties, using only a topical treatment but our dog was showing signs of relief within days. We did end up also using Fleabuster powder to control fleas in the carpet faster as there is a baby but honestly, Frontline has been working great for my dog. Recommend it

Rated 5 out of 5 stars
By james on Dec 18, 2025

I've been using it for years

I first tried it when it came out and have used it on all my dogs with good protection and no side effects

I first tried it when it came out and have used it on all my dogs with good protection and no side effects

Rated 5 out of 5 stars
By Christine on Nov 23, 2025

A safe flea and tick treatment

The treatment lasts for 30 days, so it is not too strong for my pets. I don't want to poison their system with long-lasting product.

The treatment lasts for 30 days, so it is not too strong for my pets. I don't want to poison their system with long-lasting product.

Rated 2 out of 5 stars
By Toni on Sep 12, 2025

Caused Reaction for My Dog

I’m giving this two stars since the ease of use and price of this product are convenient, however, my dog has been miserably itchy since we put the medicine on her

I’m giving this two stars since the ease of use and price of this product are convenient, however, my dog has been miserably itchy since we put the medicine on her. She developed dandruff along her back where the medicine was applied and has red patches all over her stomach.

Rated 5 out of 5 stars
By Erin on Dec 20, 2025

Worked great

Noticed less itching in 24 hours and hasn't returned. Buying their second month dose now!

Noticed less itching in 24 hours and hasn't returned. Buying their second month dose now!