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K9 Advantix

K9 Advantix II XL Dog Vet-Recommended Flea, Tick & Mosquito Treatment & Prevention | Dogs Over 55 lbs. | 4-Mo Supply

  • Based on 36,478 reviews
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Size: 4 Pack


Features

  • K9 Advantix II Extra Large Dog 30-day treatment & prevention protects dogs over 55 lbs. from fleas, ticks, mosquitoes, biting flies and lice
  • Kills fleas within 12 hours of application
  • Vet-recommended formula kills & repels on contact so fleas dont have to bite your dog to die
  • Easy-to-apply topical treatment is fragrance-free and waterproof after 24 hours
  • No prescription needed

Description

K9 Advantix II Extra Large Dog is the veterinarian-recommended formula that helps defend your dog against five pests: fleas, ticks, mosquitoes, biting flies and lice. And unlike other treatments, K9 Advantix II kills and repels fleas, ticks and mosquitoes. K9 Advantix II topical treatment gets straight to work killing fleas on dogs within 12 hours of initial application. This formula stops existing flea infestations and prevents new ones by killing adult fleas on contact so they canā€™t lay eggs and they donā€™t have to bite your dog to die. Fleas, ticks, mosquitoes and other pests not only cause discomfort; they may also transmit disease. Monthly use of K9 Advantix II is important to protect your dog against fleas that may cause transmission of tapeworms. This formula also kills fleas which may cause Flea Allergy Dermatitis and flea bite anemia. Thatā€™s why K9 Advantix II Extra Large Dog topical, spot-on formula makes application simple - going on in seconds. It's easier than a flea collar and there are no hard-to-swallow pills. Youā€™ll also love that K9 Advantix II is fragrance-free and waterproof after 24 hours of application. Check the product label for information on application and potential side effects. K9 Advantix II pest protection is effective on both indoor and outdoor dogs. Your dog should be at least 7 weeks old and weigh over 55 lbs. to use K9 Advantix II Extra Large Dog. For the ultimate convenience in care, K9 Advantix II is available over the counter ā€“ no prescription needed. And, you can stock up with 2-dose, 4-dose and 6-dose packs so you never miss a monthly treatment. Once K9 Advantix II is applied, your dog is ready to get right back to big-pup cuddles and racing around the park. K9 Advantix II Extra Large Dog is a trademark of Elanco or its affiliates.

Brand: K9 Advantix


Item Form: Topical


Scent: Unscented


Item Weight: 1.6 ounces


Active Ingredients: Imidacloprid, Permethrin, Pyriproxyfen


Item Volume: 16 ml


Allergen Information: Allergen-Free


Dog Breed Size: Large


Unit Count: 4 Count


Color: Extra-Large Dog only


Product Dimensions ā€ : ā€Ž 1.38 x 4.38 x 4.75 inches; 1.6 ounces


Item model number ā€ : ā€Ž 86315017


Department ā€ : ā€Ž Unisex-Adult


Date First Available ā€ : ā€Ž October 5, 2004


Manufacturer ā€ : ā€Ž Elanco US Inc


Best Sellers Rank: #517 in Pet Supplies (See Top 100 in Pet Supplies) #6 in Dog Flea Drops


#6 in Dog Flea Drops:


Customer Reviews: 4.5 4.5 out of 5 stars (36,478)


Brand Name: K9 Advantix


Unit Count: 4 Count


Age Range Description: 7 weeks and older


UPC: 724089204103


Global Trade Identification Number: 03


Included Components: 4


Item Type Name: Topical


Manufacturer: Elanco US Inc


Model Number: 86315017


Manufacturer Part Number: 86315017


Warranty Description: No_warranty


Item Form: Topical


Scent Name: Unscented


Dog Breed Size: Large


Target Species: Dog


Item Weight: 1.6 ounces


Volume: 16 ml


Allergen Information: Allergen-Free


Active Ingredients: Imidacloprid, Permethrin, Pyriproxyfen


Frequently asked questions

No, the K9 Advantix II XL is intended specifically for dogs over 55 pounds. Using it on a smaller dog may result in an overdose, as the doses are tailored to the weight of the dog.

Yes, the K9 Advantix II remains effective after bathing, water immersion, or exposure to sunlight.

This product is designed for monthly use. Just one application per month provides multi-stage flea, tick, and mosquito protection. Overdosing can be harmful to your pet.

Some dogs may experience temporary irritation at the application site. If signs persist or become severe within a few days of application, consult your veterinarian immediately.

Similar Products

Top Amazon Reviews

šŸš€ Abunda's Overview

This is our summary and key points to consider based on customer reviews.

These reviews overwhelmingly suggest a positive customer experience with K9 Advantix II flea and tick medication. It's praised for relieving dogs of itching and discomfort caused by pesky intruders such as fleas, ticks, biting flies, and mosquitos. Users report that the product is reliable and effective across different dog breeds and sizes, providing quick relief and consistent results. Some reviewers express their loyalty to this brand, stating it outperforms its competitors.

Pros

  • šŸ¾ Highly effective against a range of parasites like fleas, ticks, mosquitoes, and biting flies
  • šŸ• Works consistently across different dog breeds and sizes
  • šŸ’Ŗ Trusted by loyal users as a superior product compared to competitors
  • šŸš€ Provides quick relief from discomfort caused by bug bites

Cons

  • šŸ’ø A bit on the expensive side, especially for larger packs
  • šŸ“¦ Concerns about packaging, with one customer reporting receiving an opened box

Should I Buy It?

Absolutely. Considering the high effectiveness, reliable results, and customer loyalty towards the product, purchasing K9 Advantix II appears to be a wise investment for your dog's health and comfort. Just keep in mind, it's slightly pricier than some other options on the market.

    • Reliable product - highly recommend - works !!!
Size: 1 Pack
Review Image by sntj
Always use this brand flea preventative . It kills many critters trying to annoy and hurt my pups . I want my fur covers kids just as safe as my flesh covered kids ;) The product is the best for fleas ticks and mosquitos . And in this heat and lack of freezing temps , ticks and rad and skeeters are running ramped out there . The size depends on your dogā€™s weight please read their chart within the ad . Then there are single dose , 2 pack, 3 pack and 6 packs available . It is to be used once a month . Imagine this .. the liquid seeps into your pets skin and spreads around via the oil in the skin . It gives them complete protection as far as coverage . There is not a spot a flea can bite them and survive . Most fleas and ticks will be repelled by the scent that we cannot smell once it is ā€œ in/ on ā€œ them . It uses your pets natural body chemistry to help it work better . You should wait at least 2 days after giving a bath to use flea protection like this . The pet needs to replenish the oils that a bath(shampoos) dries out . Then it will work better . Do not use on wet skin either . It is best to separate the hairs on your let until you see skin ( best spot usually base of back of neck where they cannot reach or lick it ) Then place the vial to the skin and squeeze gently . Be aware of your eyes !! If you have larger dogs there is more in the vial so I will do one spot then spread hairs next to that spot and apply rest in same area but different spot This way it all sinks in and it wonā€™t run onto the hair and clump up . If it does leave it for now let it all dry after a day just brush the spot to eliminate a tangle . I have been using this product for as long as I can remember and the animal hospital I worked at recommend this product as well . It will treat more than frontline plus will . I feel better also. My dogs donā€™t itch all the time . There have been no reactions or issues from this product on their skin . IF ingested by pet they need to be taken to ER right away . And if ingested by humans as well-ER move it move it move it !!! Poisonous if ingested or gets into eyes of you or pet. I like the snap open vial better than the get scissors and cut open vial Doing that can cause a squirt . I always look other way when opening these and never near pets face . Always wash hands with damp after applying to pet asap. A very durable reliable product for your and your babies . A size for every pet and peace of mind for every owner / parent ... show more
Reviewed in the United States on August 5, 2026 by sntj
    • Certainly the Best for Ticks
Size: 6 Pack
Review Image by Bastian
My dog is a Great Pyrenees at 100lbs. I use one of these per month as per the directions. Never knew if it worked until today. Found a handful of ticks I picked off in the parking lot after some grass on my dog, then one more 30 minutes later when I got home on her inner thigh that was half curled up and unresponsive. Hours later even after a thorough tick check I find what looks like dirt on her tail area, picking it up with a glove to see it was a deer tick completely dead and unresponsive. No ticks had ever bitten her at all. Fantastic product! Saves my dog, me, and anyone else in my household - they donā€™t just fall off they just die. Thank you! ... show more
Reviewed in the United States on May 20, 2026 by Bastian
    • Works to Keep My Home Flea Free
Size: 1 Pack
This is My go to for flea protection. My vet recommended these drops and since we havenā€™t had dogs, we have always used them, and I have never found a flea. After we put these on, we always have to make sure that we do not put their backs until it is nice and soaked in. Once it has soaked into their skin and we are able to give them a bath to get rid of the oily spot where we applied the medication. I have found these straps to be safe to use, I have never noticed any scratching or skin irritation. This product has protected my dogs, my yard and my house for over 5 years. ... show more
Reviewed in the United States on July 18, 2026 by Tracey Campbell
    • GENUINELY WORKS!!!!
Size: 4 Pack
Soon as I applied to my dogs AFTER FOLLOWING THE DIRECTIONS ON THE BACK mosquitoes definitely ignored my dog and cane straight towards mešŸ¤£ But definitely recommend bathing your fur babies and applying the medicine when they are completely dried. DEFINITELY ONE OF THE BEST TREATMENTS OUT THERE!!!!
Reviewed in the United States on July 11, 2026 by Fredo
    • The safest and most effective tick protection - ticks fall off just from touching the fur
Size: 6 Pack
I brought my dog to West Virginia, and thank God for Advantix II ā€” because Iā€™ve been finding half-dead ticks every single day (no joke) in places where she sleeps or rests. At first, I was confused. I thought "repels ticks" meant it would work like bug spray does for mosquitoes, keeping them away completely. But after looking into the active ingredient, permethrin, I realized that in this case, ā€œrepelā€ means: once a tick touches the treated fur, it becomes so irritated or neurologically impaired that it canā€™t bite, canā€™t hang on, and eventually just falls off and dies. Thatā€™s still so much better than PetArmor, Frontline, or any of the oral preventatives (like Simparica or NexGard), which require the tick to bite the dog before it dies. No thanks. Every tick Iā€™ve found so far had already dropped off my dog before it had a chance to bite her and feed ā€” exactly what you want in a tick-heavy area. Iā€™ve also tried Wondercide (cedar oil). It works okay for fleas, but itā€™s just not effective for ticks, especially not in the long term. Its protection wears off after 2ā€“4 hours. I learned the hard way ā€” my dog caught Lyme disease, developed joint pain and a limp. Thankfully, doxycycline helped and sheā€™s okay now, but it required a full 28-day antibiotic course. I would never use oral flea/tick medications. Just ask around ā€” youā€™ll hear plenty of stories about dogs having seizures after taking them. For me, that risk isnā€™t worth it. If you have a cat at home, unfortunately Advantix II may not be right for your household ā€” permethrin is toxic to cats (especially when wet). But if you donā€™t have cats, I highly recommend this product to all dog owners. Tick-borne diseases are no joke. Fleas are annoying ā€” Iā€™ve had to go through the nightmare of clearing an infestation ā€” but at least they just suck blood without causing life-threatening illness. Ticks, on the other hand, can transmit Lyme, Ehrlichia, Rocky Mountain spotted fever, and more. So if you live somewhere warm, humid, grassy, or deer-heavy ā€” do your dog a favor and get Advantix II. Itā€™s been a lifesaver for us. ... show more
Reviewed in the United States on June 4, 2025 by yishin
    • It works and works fantastically
Size: 6 Pack
I've been using K9 Advantix (I and II), and I've never had to worry about ticks, fleas or mosquitos, and I live out in the woods in a state that has these critters *everywhere*. My dogs walk all around in the fenced off area of ~4 acres, which I keep mowed to 3.5 inches and only a few trees in the main backyard but a .5 acre cedar grove in the front of the house. Cedar keeps the climbing bugs at bay well enough, but walking the fence line in the back and around the 100 yd x 50 yd pond and I have to check for ticks on me when I get in. The dogs will have a couple on them, but they never get the chance to dig in, so leaving them outside a lot of the day and night doesn't concern me. When they're inside, wherever they sit or lay, they're leaving an extremely small bit of this stuff on the material that also kills the crawling critters. The pond, naturally has mosquitos, but they don't hardly land on the dogs...unfortunately they DO land on me. As I said, I've used this stuff for decades on my dogs and because of it they're not uncomfortable from biting insects and the mosquitos pretty much leave them alone or die after lighting on them and don't infect them with heartworms. Also, this is like water, so when putting it on the dogs you need to put it in several spots on their back for it to work best. Because it's a water-type stuff, no more messy, gunky oil-based junk to get all over your hands or places they lie or collect dust/dirt/etc. Overall this can't be beat since it covers pretty much any critters that would love to make a home on your dog. ... show more
Reviewed in the United States on June 8, 2026 by Yonaton
    • My go to for Flea and tick prevention.
Size: 1 Pack
After trying several different flea and tick treatments over the years, K9 Advantix has consistently been one of the most effective options for my dog. Application is quick and straightforward, and within a short time I noticed a significant reduction in fleas. Living in an area where ticks are common, itā€™s reassuring to know my dog has reliable protection during walks, hikes, and time spent outdoors. One thing I appreciate is that it doesnā€™t leave a heavy, greasy residue once itā€™s had time to dry, and my dog hasnā€™t shown any signs of irritation after application. Following the recommended dosing schedule has kept the protection consistent month after month. The peace of mind alone makes it worth the investment. Keeping fleas and ticks under control is much easier than dealing with an infestation, and this product has helped do exactly that. Based on my experience, K9 Advantix is a dependable choice for pet owners looking for effective, easy-to-use flea and tick protection. ... show more
Reviewed in the United States on July 9, 2026 by robert kinnunen
    • Works great awesome I definitely suggested
Size: 4 Pack
Review Image by ARBONNE
UPDATE I donā€™t know what yā€™all all your people take your dogs to the vets instead of showing them online here that they canā€™t walk. The fur is falling out of the bleeding. Thatā€™s ridiculous. Take your dog to the friggin neck. Let the vet determine the cause exactly and then if itā€™s in clause because of this then Put a negative and state the fact that you took him to a vet and the vet did test and it was the closet because Iā€™ve been using this product for 25 years on my dogs back then and my new dogs now my dogs I had 16 years ago dogs I had 10 years ago dogs I had 13 years ago my 16 1/2 year old cocker spaniel has had this from the day he could actually have this And I have never had a problem with that on any of my dogs especially him you know it got rid of the fleas and I noticed a few texts very easy to get off compared when I didnā€™t use it like if I skipped a couple of months and they had a dick and I was like oh my God and then I would try to get it off and it was a hassle. I mean, it did not pull up. Come out whatever And so I put them back on this every month originally and if they get a tick and I see it. I just need tweezers and it just pops right off no eggs inside nothing no problem with the weather did not cause any of my dogs ever itch or lose hair so I think you people have an undergoing problem with your dog that you did not address Prior to use this. Yes, Iā€™m gonna blame you. Yes Iā€™m blaming all you that people that has undermining problems with their dog and you donā€™t take them to the vet and you add this product on top of them. Yes, it probably will do something like that. SO I REPEAT, TAKE YOUR DOG TO THE GD VETERINARIAN PROFESSIONAL LET THE PROFESSIONAL DO THEIR WORK !!!! Oh, I also have one dog right now. I have three of them English mastiff and I have one of them that sits at my back gate in the dirt never has fleas never has sticks never has any. He lays in the dirt 185 pound and his head I can look it out right now his head is in it. His whole body lengthwise is in it and I swear he digs holes just you know it makes it cool.. and thereā€™s a picture of him laying at the fence in the dirt. He loves it. I check them every day. Nobody has fleas. Nobody has anything so you people are doing something wrong. Iā€™m gonna blame all of you. They have a problem and Iā€™ll say it again again again they have underlining problem TAKE THEM TO THE VET VETERINARIAN HAVE THE VET, VETERINARIAN, TECHNICIAN, AND DOCTOR EXAMINE THE DOG TAKE SKIN GRAPHS WHATEVER THE BEST HAS TO DO. DONā€™T BLAME THE PRODUCT UNLESS YOU DID THAT AND IF YOU DID IT AND THEN DOCTOR RUNS TEXT AND SAID YES, IT WAS CAUSED BY THAT PRODUCT. WELL HENCE THERE YOU GO AND ITā€™S THE PRODUCT FAULT BUT A 99.999% ITā€™S NOT THE PRODUCT. Started having dogs when we first got married we have we had seven English mastiffs yeah itā€™s addicting and they had puppies and everything so anyways Iā€™ve been using this on my dogs from year 2000 and I use them before that on my other dog so Iā€™ve always used it really and I love it. I mean, I swear by it this stuff is great. My dogs do not get flea or I mean I have to put a spray on them to detail the mosquitoes, but donā€™t see my bugs biting them. Itā€™s pricey, but itā€™s worth it. You donā€™t wanna have your dogs get Lyme disease or you know from ticks, I really suggest this. No bother my dog knock on wood you know in the other thing is I donā€™t use this year around. I only use it from spring until after fall. I donā€™t feel I really needed in the winter time. Itā€™s too cold outside for anything to live so Iā€™m up Northeast And I donā€™t seem to have any problem and theyā€™re not using it as soon as spring hits thatā€™s that boom theyā€™re on it. ... show more
Reviewed in the United States on July 3, 2025 by ARBONNE

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