1. Home > 
  2. Dog Supplies > 
  3. Flea & Tick Supplies > 
  4. Topicals > 
  5. K9 Advantix II for Dogs: Flea & Tick Control > 
  6. 12 MONTH K9 Advantix II RED for Large Dogs (21-55 lbs)

  • Back of box showing precautionary statements and directions for useBack of box showing precautionary statements and directions for use
  • Dog silhouette connected to pictures of harmful insectsDog silhouette connected to pictures of harmful insects
  • Banner reading frontline plus does not repel. K9 Advantix two kills and repels fleas, ticks, and mosquitoes above those three insectsBanner reading frontline plus does not repel. K9 Advantix two kills and repels fleas, ticks, and mosquitoes above those three insects
  • Banner reading kills through contact no biting requiredBanner reading kills through contact no biting required
12 MONTH K9 Advantix II RED for Large Dogs (21-55 lbs) Video

12 MONTH K9 Advantix II RED for Large Dogs (21-55 lbs)

Compare to: $170.99
and Ships Free!*
You Save: $40.00!(23%)
Keep your dog safe from irritating and dangerous pests with K9 Advantix II for Large Dogs weighing 21-55 pounds. Formulated for dogs seven weeks of age and older and weighing 21-55 pounds , K9 Advantix II outperforms its competitors not only by killing more varieties of pests, but also by repelling them to prevent future attacks.


K9 Advantix II is one of the top choices for eliminating the resident tick or flea population. It is manufactured by Bayer, one of the leading pet care companies in the world. This product promises to kill and repel ticks, fleas, and mosquitoes. Its waterproof formulation remains effective even after the pet gets wet. The K9 Advantix II solution works by attacking all the life stages of the parasites killing adult bugs, larvae, and eggs. The K9 Advantix II Red is a specialized product for large dogs weighing 21-55 lbs. This particular pack contains 4 doses, which is good for 4 months of protection against ticks and fleas.

  • For large dogs weighing 21-55 lbs
  • Manufactured by Bayer
  • Waterproof formulation
  • Repels ticks, fleas and mosquitoes
  • Kill parasites of all life stages
  • For dogs only


Imidacloprid: Imidacloprid is an ectoparasiticide, an antiparasitic agent that targets parasites living primarily on the surface of a host. Chemically classified as a chloronicotinyl nitroguanidine, imidacloprid inhibits neurotransmitter transmission in insects, resulting in paralysis and death.

Benefits: Imidacloprid exhibits both adulticide and larvicidal flea efficacy; it not only kills adult fleas and larvae on your pet, but it also kills larval stages in your pet's immediate surroundings.

Main Purpose: To kill fleas at all stages of their life cycles and stop them from being able to move or feed.

Permethrin: Permethrin is the additional ingredient in Advantix. It belongs to the Type I class of pyrethroid acaricides and insecticides, and it also acts as a repellent. Pyrethroids affect muscle and nerve cells' sodium ion channels by increasing their mean open time, which leads to hyperexcitability and death of the parasite.

Benefits: Thanks to its repelling activity, permethrin reduces parasite bites and thus the risk of diseases and stress for your dog.

Main Purpose: To repel ticks, sand flies, and mosquitoes; to kill ticks and fleas.

Two Proven Ingredients with Enhanced Activity: Imidacloprid and permethrin work together to overwhelm the nervous system of the parasite, providing neurotoxic activity beyond that of each compound alone. This leads to more profound and quicker insect paralysis and death.

Specifically, imidacloprid increases the efficacy of permethrin by activating insect nerve cells and increasing the frequency of neurotransmissions. As a result, more sodium channels are opened and the pyrethroid can interact much better with its target site.

Pyriproxyfen: Pyriproxyfen is a pyridine-based pesticide. A juvenile hormone analog, it interferes with the hormone signaling of growing insects, so that insects in immature stages are unable to mature. Additionally, a female insect that touches the toxin will produce eggs that will not hatch.

Benefits: Pyriproxyfen provides an added layer of protection for pets and their surroundings. It interrupts the flea life cycle at multiple stages, halting the growth and development of insect eggs and larvae and preventing re-infestation.

Main Purpose: To prevent flea eggs from hatching and larvae from growing.

Active Ingredients % by Weight
Imidacloprid 8.80%
Permethrin* 44.00%
Pyriproxyfen 0.44%
Other Ingredients 46.76%
Total 100%

Useful Information

Applying K9 Advantix II to your pet is a fast and easy process. First, remove the K9 Advantix II applicator tube from its packaging and use scissors to peel down the foil. Next, hold the applicator tube in an upright position and pull the cap off the tube. Use the upturned cap to break the protective seal, and you're ready for application.

For easiest application, your dog should be standing upright. Evenly apply the entire contents of the K9 Advantix II tube to two or three spots from the back of the shoulder to the base of the tail. Part the hair at each spot until the skin is visible, then place the tip of the tube on the skin and gently squeeze out a portion of the solution. Be careful not to apply an excessive amount of the solution in any one spot, otherwise some of the solution might run off the side of your dog. Dispose of the container and do not reuse or refill. Do not empty unused product in any indoor or outdoor drain.

For optimal control and prevention of parasites, use K9 Advantix II every month. K9 Advantix II is available in four- and six-month supplies. Do not use K9 Advantix II on cats or any animals other than dogs.

Application Instructions: Evenly apply the entire contents of the tube to four to six spots on the top of the back--from the shoulder to the base of the tail. Apply monthly.

Length of Effectiveness: Under normal conditions, the product is effective for one month. However, in cases of severe flea infestation, re-treatment may be necessary earlier than four weeks. Do not retreat more often than once every seven days. After flea control is attained, return to a monthly re-treatment schedule.

Hazards to Humans: Causes eye irritation. Harmful if swallowed. Do not get in eyes or on clothing. Avoid contact with skin. Wash hands thoroughly with soap and warm water after handling.

Hazards to Domestic Animals:

*For external use on dogs only. *Do NOT use on animals other than dogs. *Do NOT use on puppies under seven weeks of age.

Do not get this product on dog's eyes or mouth. Consult your veterinarian before using this product on debilitated, aged, pregnant, or nursing animals. Individual sensitivities, while rare, may occur after using any pesticide product for pets. If signs persist, or become more severe, consult a veterinarian immediately. If your animal is on medication, consult your veterinarian before using this product.

Do Not Use on Cats: Due to their unique physiology and inability to metabolize certain compounds, cats must not use this product. If applied to a cat, or ingested by a cat that actively grooms a recently treated dog, this product may have serious harmful effects. If this occurs, contact your veterinarian immediately.

Environmental Hazards: This product is extremely toxic to fish. Do not add directly to water. Do not contaminate water when disposing of product or package.

    First Aid: Have the product container or label with you when calling a poison control center or doctor, or when going for treatment.

    If in eyes: Hold eye open and rinse slowly and gently with water for 15 to 20 minutes. Remove contact lenses, if present, after the first 5 minutes, then continue rinsing eye. Call a poison control center or doctor for treatment advice.

    If swallowed: Call poison control center or doctor immediately for treatment advice. Have person sip a class of water if able to swallow. Do not induce vomiting unless told to do so by the poison control center or doctor. Do not give anything by mouth to an unconscious person.

    If on skin or clothing: Take off contaminated clothing. Rinse skin immediately with plenty of water for 15 to 20 minutes. Call a poison control center or doctor for treatment advice.

    To physician: Treat patient symptomatically.

Keep out of reach of children.

Customer Reviews

55 Reviews
85% (47)
9% (5)
4% (2)
2% (1)
0% (0)
98% Recommend this product (54 of 55 responses)
By sadie2peanut
Los Angeles, CA
April 24, 2017
K9 advantix II
I have used this product in different strengths for my different sizes of dogs for many years. My pets have been flea free and have not been bothered by our many mosquitoes and they have never had a tick. I recommend it to anyone with dogs.
By Gump
Bloomfield, Ontario
March 29, 2017
Count on this
We have used K9 Advantix II on our dogs for 3 years now, and we live in an area that supposingly has lots of ticks...I wouldn't know as we have not been bothered with them as we have always used this product. I highly recommend it!"
By Deb
November 3, 2016
Works Great
We've been using Advantix II on our beagles for years. We live in the Midwest so we really need to make sure that our pets are protected from mosquitoes, fleas and ticks. Advantix II has never failed us. Now we have a third beagle and we will be using Advantix II on her as well.
By Birdikins
Bellingham WA
July 29, 2016
Advantix Flra Treatment
For several years, I have been buying my flea treatment from Entirely pets. This has saved me a considerable amount of money over purchasing it at the vet...or even at Costco!

Advantix is an excellent product.

Entirely Pets is an excellent marketplace
By Tinmanjack
Port Monmouth, NJ
July 9, 2016
Single Coverage
Having 3 Brittany's of different weight, K9 Advantage II is the only flea and tick protection I found that one package covers the weight range of my 3 dogs.
June 14, 2016
Excellent one stop shop
This product most effectively protects my dogs against all the most common pest that attack them. I highly recommend it. The only caution is that it needs to be put on with great care, through thick hair and fur, right onto their skin and it must be put on in a way that it is not accessible to their tongues.
By Henry711
Smyrna Beach Florida
April 27, 2016
Good overall value
Product seems to cover all of the essential protection. Recommend by our vet
By Linseed
March 23, 2016
Best product for fleas and ticks
This is not my first time purchasing this product. It works very good, especially on fleas. I noticed that one of my dogs that has a lot of hair have a few fleas and one of my other dogs that has short hair also had a few fleas, I would just put the product on th dog with a lot of hair and it would also eliminate the fleas on my short hair dog even though I didn't put it on my short hair dog. So I consider that it it a very good product. Thank you.
By Gina
March 15, 2016
Great product
I've been using this product for years and it is great for repelling fleas and ticks.
By Dee
Columbus, Oh
March 24, 2015
K9 Advantix ll
Our dogs are flea and tick free with this product, never had any problems with it not working.
By Tony R.
August 7, 2014
Best Flea and Tick Product for Dogs
We have tried cheaper products to control flea and ticks on our 4 dogs, but we have come back to this product because it is the only one that works for us. We also find the price to be very good and auto delivery perfect for us.
By Dogfriend
June 19, 2014
Review for 12 MONTH K9 Advantix II RED for Large Dogs (21-55 lbs)
This product performs better than Frontline but still lacks the ability to kill fleas for 30 days. My dogs still get fleas on them that this product does not kill. Have to supplement with Capstar. Do not like it being oil based instead of water based. Be careful of staining your furniture until product completely dries on your dog.
By Cooch
Pepperell, MA
May 25, 2014
Great protection
I haven't seen a flea or tick on my dog since I started using Advantix II.
By garya
May 21, 2014
K9 Advantix
Best price I could find on line and fast shipping.
Will use again for more supplies.
By Fritz
April 21, 2014
On-going best deal
I have used Entirely Pets over the last several years and they continue to be the best deal out there, both in pricing and the speed of shipments!
By pippalou
April 4, 2014
Great for tick and flea prevention
I started using K9 Advantix a couple of years ago. My dogs are out in the woods a lot, so they tend to be where ticks are, and our previous tick treatment didn't seem to work so well. I changed to K9 Advantix, and it worked much better at keeping the ticks off. I highly recommend it for ticks and fleas.
By rich
April 2, 2014
Excellent Value
This is a very good product. I want to keep my dog protected.
By Pat
Scotia, NY
July 7, 2013
Great for repeling mosquitos, fleas and ticks
Nothing better to keeping the dogs free of nasty parasites.
By Karen
June 26, 2013
K9 Advantix II
This product is great- HOWEVER, the recommended dosing causes neurological issues in ALL four of my dogs. I have to buy the size rated for the next one down. For example, if my dogs weigh 40 lbs, which they all do plus or minus a pound or two, I should be buying the LARGE dog 21-55 lbs. This is too much for them and I've heard this from many family members also and they buy the next size down, which is medium 11-20 lbs. Maybe they need to relabel these since last I knew, forty pound dogs arent large anyway, to me a large dog would be a pitbull or german shepard or something.
By Christine
Sterling, Ma
June 20, 2013
I love this product. I have used it for years and will continue to do so. Entirely Pets is very cost comparitive as well....best place to shop for your pets supplies and needs.
By peg
April 1, 2013
Does the job!
I've been using this for quite some time and find it does what it is designed to do--kill fleas and ticks.
By lv
March 17, 2013
comfort for dog
I used to use Frontline Plus for my dog and it worked just fine but we are in an area that has lots of mosquitos so i switched to Advantix and it seems to work as well as the other. I will keep using it.
By Barb
March 11, 2013
When top spot became less effective...
I switched to K-9 Advantix when Top spot became less effective. Over time, many products can lose their effectiveness and it is good to know their are others that can be used just as well.
By Cece
February 6, 2013
Solved Flea Problem
Unexpectedly got a flea problem in the house. This product with vacuuming and washing insures control of any remaining pupae emergence with life cycle control.
By Guiness
January 23, 2013
Product great
Price the best anywhere
Service and delivery great
By Mark
Clifton, Virginia
January 12, 2013
Excellent Product
We have been using Advantix for our 5 dogs for several years - in that time they had no ticks or any other parasite. It works.
By Barry
Southern Maryland
January 8, 2013
Advantix for tick/flea protection
This product generally works well. Easy to apply. During the height of tick season, I might still find an occassional tick on our dog. Most often, the tick s aleady dead or dying. Not always though which may mean the tick has not been on our dog long enough for the medicine to have killed the tick. An ideal product of this nature would stop ticks from even alighting or staying on the dog, but perhaps that is asking too much,
By Cocker F.
January 6, 2013
Great Deal & Great Product
Having four cocker spaniels, I am always looking for the most economical way to care for my furry friends. Entirely Pets allows me to do so with top-of-the-line products! K9 Advantix II is highly effective. I have not found a flea or tick on any of my dogs since I've started using it. I am extremely happy with this product and will continue to purchase it.
By KinPA
The Poconos, PA
December 18, 2012
K9 advantix II
I just love this product. I prefer it over the Frontline Plus. Keeps the fleas etc. off the dog. Great product.
By Sage
Grand Rapids, MI
December 7, 2012
Helped our dogs get rid of fleas
I didn't realize our 17 year old dog had fleas, but when I saw the little black specs I realized she needed help. So I purchased the Advantix and it did help kill the fleas and I do not see black specs on her any more.

Questions and Answers

There are no questions or answers for this item.

CALL IN YOUR ORDER 800.889.8967

Stay in touch. Friends fur-ever!

Terms and Conditions

You have to agree on terms in order to proceed to the subscription.