Search  for anything...
K9 Advantix

K9 Advantix II Flea & Tick Topical for Large Dogs 21–55 lbs., 6ct

Based on 44,688 reviews
Condition: New
Checking for the best price...
$79.92

Buy Now, Pay Later

As low as $13.32 / mo
  • – 6-month term
  • – No impact on credit to apply
  • – Instant approval decision
  • – Secure and straightforward checkout

Ready to go? Add this product to your cart and select a plan during checkout.

Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Zip, Apple Pay, and Google Pay. No-credit-needed leasing options through Acima may also be available at checkout.

Learn more about financing & leasing here.

Selected Option

Free shipping on this product

FREE 30-day refund/replacement

To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

Availability: In Stock.
Fulfilled by Amazon
Arrives Wednesday, Oct 28
Order within 1 hour and 52 minutes

Available payment plans shown during checkout

Protect Your Purchase

Easy claims online, fast replacements, no fees

Checking for protection plans...

Recently Viewed

At a glance

Condition
New
Size
6 Pack
Dimensions
7.75 x 1 x 4.25 in; 0.32 oz
Weight
9.07 g
Color
Large Dog only
Item Form
Drops
Scent
Unscented

Features 5

  • 5-WAY PROTECTION: For 30 days, 1 dose of K9 Advantix II treats and prevents fleas, ticks, mosquitoes, biting flies, and lice on dogs; DO NOT USE ON CATS
  • SAME-DAY FLEA CONTROL: These tick and flea drops for dogs kills fleas on dogs within 12 hours of application, helping provide relief from active infestations
  • REPELS & KILLS THROUGH CONTACT: K9 Advantix II kills and repels fleas and ticks through contact, so they don't have to bite your dog to die
  • VET-RECOMMENDED*: K9 Advantix II for Dogs is vet-recommended* flea, tick, and mosquito treatment and prevention without a prescription *Elanco Animal Health. Data on file. REF-23998

Description

K9 Advantix II 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 can’t lay eggs and they don’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. That’s why K9 Advantix II 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. You’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 21-55 lbs. to use K9 Advantix II Large Dog. For the ultimate convenience in care, K9 Advantix II is available over the counter – 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 Large Dog is a trademark of Elanco or its affiliates.

Specs 25

Brand K9 Advantix
Item Form Drops
Scent Unscented
Item Weight 9.07 g
Active Ingredients Imidacloprid, Permethrin, Pyriproxyfen
Item Volume 1 quarts
Allergen Information Allergen-Free
Unit Count 6 Count

Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Wednesday, Oct 28

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

  • Klarna Financing
  • Affirm Pay in 4
  • Affirm Financing
  • Afterpay Financing
  • Zip Pay in 4
  • Financing through Apple Pay
  • Financing through Google Pay
Leasing options through Acima may also be available during checkout.

Learn more about financing & leasing here.

Similar Products

Top Amazon Reviews

It works
Size: 2 Pack Style: Large Dog only
My dog was on a prescription medication before this. I had to stop her previous medication because it was out of stock for a while and when it was restocked, the price skyrocketed to $250 for a 6 month supply instead of the usual $120 that it was prior. There was a new generic version of her prescription but after reading the reviews on that, I didn’t want to risk my dog’s health. During that time of her not being on any preventative, we ended up with a flea problem in my area which we never had before. Since the fires, a lot of wildlife has been dropping by in my neighborhood and with wildlife comes fleas just hitching a ride with them. We fell victim to an infestation in our backyard and surrounding areas. I panicked and tried the holistic approach for months with DE, changing my dog’s diet, essential oils, etc to no avail. I had to try something because my dog is old and I really didn’t want to stress her by taking her to the vet for yet another prescription (which all had extremely negative adverse effects after doing plenty of research). I decided to try an OTC flea treatment and it was between this one and frontline. After doing more research, I opted for Advantix II since it was more effective than frontline (for my area). So glad I did because fleas were gone within a day. My dog has been on this for a year now and so far it is working. I did find a flea on her the other day right after we got back inside from our little walk and was able to grab it. I put it in a ziplock bag with a piece of my dogs shedded fur just to see if the treatment was still working since it had been 26 days since I used Advantix and within 2 hours of that flea crawling on her fur in that bag, it was dead. So I know for sure that this medication is working and working effectively at that. She was groomed two days prior to me finding a flea on her as well (she had a waterless bath and is wiped down with her dog wipes daily) - the bath and wipes didn’t minimize the effectiveness of this flea medication which is a huge plus! What I’ve learned throughout this whole process is that no treatment is going to immediately kill or prevent fleas or ticks - not even prescription medication - Advantix has saved me hundreds if not thousands of dollars on prescriptions and it’s still as effective as a prescription. It’s a win - win in my book and I will continue to use this year round to keep my dog protected. ... show more
Reviewed in the United States on June 10, 2025 by Amazonshopper
Worth the extra $, read the directions
Size: 6 Pack Style: Large Dog only
The directions say to NOT put it all in one spot like other brands, so be mindful of that to prevent irritation and harming your dog. I used frontline on my dog for years bc it was cheaper. But then last year I had a client that had a flea problem and I apparently brought them home with me bc my dog ended up getting infested even though she had been treated with frontline monthly. I put this on her, deep cleaned my house and sprayed everything with flea spray daily and they were gone in a week or two. I treat her with it every month now and haven't had issues. Will continue to pay the extra money as long as it continues to work. ... show more
Reviewed in the United States on June 9, 2025 by MH
Effective
Size: 1 Pack Style: Large Dog only
I've been using this brand a few years now works good on killing those nasty fleas. Easy to use just squeeze the tube of medicine on your dog try to get it down to the skin not just sitting on fur
Reviewed in the United States on June 9, 2025 by Jennifer Mann
Our dog had a severe allergic reaction.
Size: 4 Pack Style: Large Dog only
Our dog had a severe allergic reaction to this. About 2-3hrs. after we applied it he started scratching, breathing heavily and running around. I bathed him twice and administered Benadryl. He's doing much better now. We'll monitor him the next few days and find an alternative flea and tick treatment. I can't give this product a bad review because I understand it can effect dogs differently. Update 48hrs after application: Because we bathed our dog as soon as he showed signs of a reaction and administered Benadryl, we lessened the severity of his symptoms. He's not twitching or biting at his tail. His breathing is normal and he's sleeping soundly. ... show more
Reviewed in the United States on May 26, 2025 by Pap K
Advantix 11 flee and tick protection for dogs, excellent product. Adela
Size: 6 Pack Style: Large Dog only
I believe in this product , I buy a years worth for my seven dogs, it will always be a part of their care no matter the cost their well being is my priority. Adela
Reviewed in the United States on June 11, 2025 by Adela excellent product
Reliable
Size: 4 Pack Style: Large Dog only
I've used it before and I'll keep using it. My dog hasn't had any reactions or ticks. Very happy.
Reviewed in the United States on June 20, 2025 by Stephanie Exendine
Causes itching
Size: 4 Pack Style: Large Dog only
This product caused my dog (Shiba Ina) to itch at where I put it on his skin for several days. This previously never happened when using Bravecto. Can't speak to whether it works or not as he hasn't had fleas or ticks before, I'm using this as a preventative measure.
Reviewed in the United States on June 6, 2025 by Vel
Maybe a few coupons could help.
Size: 6 Pack Style: Large Dog only
Works well, dogs handle it good. Maybe the company can send out some coupons as it would help with the cost as I run a rescue here of dogs & cats.
Reviewed in the United States on June 10, 2025 by Elisa Taylor
How it works
Checking for best price...