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

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

SKU: 5461626
Regular Price: $71.99Sale Price: $49.95
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K9 Advantix II RED for Large Dogs 21-55 lbs

Keep your dog safe from irritating and dangerous pests with k9 Advantix for dogs 21-55 Lbs. Formulated for dogs seven weeks of age and older and weighing 21-55 pounds and under, K9 Advantix II outperforms its competitors not only by killing more varieties of pests, but also by repelling them to prevent future attacks.

Repels and Kills Ticks, Fleas, and Mosquitos

The active ingredients in K9 Advantix II help keep your dog safe from ticks, fleas, and mosquitoes. These effective compounds attack the pests' nerve cells, paralyzing and effectively killing them, as well as repelling them from future attacks. Most ticks are repelled and killed before they can attach, which may reduce the risk of transmitting disease-causing organisms to your pet. K9 Advantix II effectively kills and repels Deer ticks, American dog ticks, Brown dog ticks, and Lone Star ticks.

K9 Advantix II for Large Dogs up to 21-55 lbs
  • Kills and repels ticks, fleas, and mosquitoes
  • Repels biting flies and kills lice
  • Waterproof formula won't wash off from swimming or bathing
  • Includes four convenient one-month doses
  • Easy to apply
  • For dogs seven weeks of age and older and weighing 21-55 pounds and under
  • Per Dose: $12.00
Dog flea life cycle
K9 Advantix II and Frontline Plus Comparison Chart
Fights Against Fleas at All Stages of Development

K9 Advantix II protects your pet against fleas at all stages of the parasite's development. K9 Advantix II breaks the flea life cycle by killing the living fleas on your dog before they can lay eggs. It also prevents the development of existing flea eggs, larvae, and pupae, helping to prevent future infestations.

K9 Advantix II also kills reinfesting fleas (newly hatched fleas jumping back on your dog) within two hours, and it prevents fleas on a treated dog from infesting your home.

Effective Against Biting Flies and Lice

In addition to complete tick, flea, and mosquito protection, K9 Advantix II also repels painful biting flies from feeding on your dog, and it effectively kills up to 100 percent of lice within one week of treatment.

Waterproof Formula

K9 Advantix II is waterproof, so there's no need to reapply after your dog has a bath or goes for a swim. Studies show that dogs are still protected against parasites after exposure to water, though for best results, dogs treated with K9 Advantix II should be bathed with a non-detergent shampoo.

Package Contents

Box includes four 2.5-milliliter tubes of K9 Advantix II for Large Dogs 21-55 pounds.

Flea Cycle

Usage Info

How to Apply

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, retreatment 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 retreatment 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.



How long does K9 Advantix last?

A single application of K9 Advantix keeps working for one month.

How often should I use K9 Advantix?

Experts recommend monthly application to keep your dog protected year-round.

My dog is strictly indoors. Should I still use K9 Advantix?

Yes, ticks and fleas can be brought into the home by people or other pets--without owners even realizing it. Immature flea stages remain dormant until conditions are appropriate for development. This is why it is also important to protect indoor pets.

Can I bathe my dog during the month after application?

Yes, you can give your dog a bath. A non-detergent shampoo is recommended for best results.

How young can the dog be for application?

K9 Advantix is gentle enough for puppies as young as seven weeks.




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.


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 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.


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 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.


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 reinfestation.

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%
*cis/trans ratio: max 55% () csi and min 45% () trans
Net Contents

Four tubes, each 0.084 fluid ounces (2.5 milliliters)

6 MONTH K9 Advantix II TEAL for Medium Dogs (11-20 lbs)6mo Med Dog (11-20lb) K9 Advantix 2Reg price: $100.99
Sale price: $74.95
12 MONTH K9 Advantix II TEAL for Medium Dogs (11-20 lbs)12 Mo K9 Advantix II (11-20lb)Reg price: $196.99
Sale price: $148.95
6 MONTH K9 Advantix II RED for Large Dogs (21-55 lbs)6mo Lrg Dog (21-55lb) K9 Advantix 2Reg price: $101.99
Sale price: $74.95
12 MONTH K9 Advantix II RED for Large Dogs (21-55 lbs)12 Mo K9 Advantix II (21-55lb)Reg price: $200.99
Sale price: $148.95
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Customer Reviews

DISCLAIMER: The results described on the testimonials on this site, are the individual experiences and personal opinions of those who have purchased and used the products. These testimonials are not intended to make any claims that the products can be used to diagnose, treat, mitigate, cure or prevent any disease or medical condition.
Click here to see all reviews
Advantix II by Corrine from Cleveland Ohio03/20/2014

Best stuff on the market...protects your dogs from everything,,,and my dogs do not have a allergic reaction to this products like other ones...This is a little pricey, but worth it

Good Stuff by CJ10/25/2011

It seemed latley that all the different flea treatments quit working on my dogs. We tried K9 Advintix II and found it to work wonders. I especially like the fact that it controls fleas, ticks and mosquitoes.

Better than Frontline by carrolljung1 from Bennett Valley, CA10/12/2013

We have had a terrible flea problem where I live late summer and fall......Frontline was not working for my dog and for my neighbors' dogs as well. I switched to Advantix because we also have lots of ticks in the area (we live in rural Sonoma County CA) The Advantix has worked better....but our dogs still get fleas before a month on the dogs. Any suggestions????

by tdh from charlotte, nc03/13/2013

A friend of mine recommended this product after having tried several others. I decided to not waste my money doing the same thing and have been ordering this for 1.5 years. We have 2 dogs and in that time I have only seen 1 flea on one dog. However, I have had a few bite me and my indoor cats keep getting fleas.

great product by bandana from Bayboro, NC04/19/2013

Never used advantix before it works really well. so far no fleas very good value and fast shipping.

Amazing Product by wfbanker from Wake Forest NC11/29/2012

I've tried many flea products and this is the ONLY one that got rid of my dog's fleas! They were gone the next day!

Excellent product by Brittany Guy from Puyallup, WA01/08/2013

Fleas just aren't a problem after using this product.

Great price, quick shipping. by Barry02/23/2012

Much better price than through local vets.

K9 Advantix II -- A good product. by Shirl from SE TX10/17/2013

After trying this product for the first time, I am glad I did. Put this product on some young dogs that were loaded with fleas. 24 hours later the fleas were gone! Would definitely recommend this product!

Great product by kellmar11/03/2012

I used to use Advantage for my dog, but then a friend recommended K9 Advantix and it really is a better product. It helps with much more than just fleas & ticks and protects my dog from other pests. I only purchase K9 Advantix through Entirely Pets...great customer service and fast delivery!

beware -- do your research by fawvekn10/22/2012

Within days of using flea drops on my dogs, one developed acute liver failure. Luckily, and many vet bills later, she is still alive. One month later, after reapplying drops, a second dog was diagnosed with acute lymphoblastic leukemia and probably will not survive more than a month. Do some internet research on flea drops, liver failure, leukemia, seizures, and paralysis. You will be shocked. I have used flea drops for years, but I will be looking for a more natural flea remedy after these two episodes.

by LM from Providence, RI10/23/2012

I have a cocker spaniel / retriever mix and this product works well. She's outdoors a lot and likes to swim.

Pleasantly surprised by Chieko from North Carolina08/20/2014

It really does repel small knats and flies.

Great product!! by Desiree from New York08/13/2013

I have been purchasing this product for years now and have never been disappointed!!

I am so glad i bought this by dot from State College, pa10/25/2012

Our groomer insisted i buy Advantix. I finally did and the results are impressive. First, this has no odor. We were using Certifect and the stink was awful. And most importantly no ticks and we live in a heavily infested area. So i say this is the best for preventing fleas and ticks ever!

no fleas by RNDirish from WV04/23/2012

My girls have never, knock on wood, had a flea problem while using this product.

Hopeful it works! by DM07/05/2012

We are hoping this product works better than the Frontline Plus we had been using. Our dog has been having a terrible problem with fleas this year due to such a mild winter. The other product has not been effective so we were told to try K9 Advantix II. So far so good for the month but it is still early. A change in product is recommended every so often to increase effectiveness--hope it works!!

The Best Product I have used by barb1934 from Atlanta GFa11/07/2012

Excellent results after a few days use. Easy to use.

Good Product at a great price by kellyjenne05/28/2012

We've used Advantix for our dogs for the last 5 years but always bought it from our vet. This year we go the same product from EntirelyPets but paid way less then we did from our vet.

Only use this product by Nancy R. from Sacramento, CA12/09/2012

I have used this product for a number of years for my dogs. I use the one for 21-55 lbs and the one for over 55 pounds. Since we have huge yard they play outside a big part of each day in all seasons. They have never had a flea or any other kind of bug. Since one of them is a Golden Retriever, fleas could be devastating. I am thankful for this product and for Entirely Pets.

K9 advantix II by JacKay from Edenton, NC08/22/2013

I have recently adopted a chow/golden mix from the animal shelter. The owners turned him in. He was using this flea and tick preventive when he was turned in. I have been pleased with this product although the vet I use stopped selling it because it was not giving adequate protection for sand fleas. We travel to go to this vet so we do not live on the beach. The product has been fine although he does do a little scratching but I am quite sure he is flea and tick free. We live around pine trees so ticks are very prevalent and I have not seen one on him.

Wonderful product by K32011/06/2012

Very effective product. Very happy with the results!!

by agriffin66 from Tifton,GA05/10/2013

Useless product. Opened it first so I could not return it. Product was o too small,My dog is 80 pounds! Your error not mine. Will buy elsewhere.

Wow! by Ellie Mae from Florida08/21/2013

We've been using another popular brand for years because it also treats for ticks. We live near a wooded area where ticks attack. This dog is unable to take internal flea meds due to pancreatitis and suffers terribly from the flea bites. So, just as horse owners rotate those wormers, it seemed that a change in flea meds couldn't hurt. Discovered that this product also treats for ticks and so we gave it a go. Our dog has now had three quiet weeks of seemingly flea free days and nights. On the down side, it is oily and our dog has silky hair so the oil spreads out and looks terrible until we can bath him. Also, we no longer have a vibrator on our bed...

love it by Diane from Sidney, Ohio02/21/2013

This product is great no more fleas or ticks.

It worked by Angie11/13/2013

I had used frontline for years, and then my dogs got fleas. All 4 of them. I tried everything, from knockout spray, flea dips, flea combs, frontline spray, bought a carpet shampooer, diatamacious earth, nothing helped. I vacuumed every day, and washed every sheet blanket, slipcover in the house every 2 days. After I applied the advantic I saw an 80% improvement within a day.

by RAMIE08/06/2012

I have used K9 ADVANTIX in the past and like the product. I use it each month including the winter months. I will continue to buy the product

Better than Frontline by Amy H from Richmond,VA11/23/2012

This summer I had serious issues with fleas to the extent that we had our yard treated. The Frontline Plus wasn't touching the problem. I switched to k9 advantix II and noticed a difference immediately.

Good Product by Jim from AL06/12/2014

I recommend this product and would purchase again.

Another quality product by Al from Pewaukee, WI06/24/2012

I've always had good results from anything I've ordered from Entirely Pets and I will continue to patronize this site.

Great on fleas & ticks by Aspen pup from Los Gatos, CA03/26/2012

Love this product, much more effective than Frontline.

K9 Advantix by BeagleBoy10/12/2013

I've used this product for the past 4 yrs and my dog has never had fleas or ticks so I'm assuming this product is very effective. Its easy to use and is very affordable.

very good product by barbie from Parsippany, NJ07/17/2013

K9 Advantix is the best product to keep mosquitos away from your dog. Mosquitos are more attracted to light or white color dogs. This was my first time using this product and not one bite since, and this year its a bad season.

K9 AdvantixII by KinPA from Stroudsburg, PA07/06/2012

Love this product. Love the fact my dog does not get fleas on his body at all. I love Entirely Pets. Great bargains all the time. thank you.

by Mary M from Saint John NB Canada06/18/2012

Timely shipment of exactly what I ordered

Great! by ltlewheaty11/27/2012

Fantastic costumer service! Fast shipping! Solid product - never any problem wiith fleas or ticks and it's not greasy or oily!


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