Advantage®, Advantage® XD Cat, K9 Advantix® II, and Advantage® Multi for Dogs and Cats

Updated Aug. 29, 2024
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In This Article

Overview

PetMD’s medications content was written and reviewed by veterinary professionals to answer your most common questions about how medications function, their side effects, and what species they are prescribed for. This content shouldn’t take the place of advice by your vet.

What Is Advantage® for Dogs and Cats?

Advantage® is a series of medications used to treat and prevent flea infestations in cats and ferrets. It is also used to treat fleas and lice in dogs. Advantage® is effective against adult fleas and flea larvae.

It’s available in several formulations (in combination with other medications) and strengths. Advantage Multi® includes the medication moxidectin, which adds heartworm, hookworm, and roundworm prevention to Advantage® for dogs and cats.

Advantage Multi® for cats also provides protection against ear mites, while in dogs, Advantage Multi® also protects against whipworm and sarcoptic mange.

It is only available by prescription, so chat with your vet to determine whether Advantage Multi® is right for your pet.

K9 Advantix® II is used only in dogs to treat, prevent, and repel fleas, ticks, lice, mosquitoes, and biting flies. It contains permethrin, a medication which is not safe for use in cats.

Advantage® XD Cat is the latest addition to the Advantage medication series, offering two months of flea protection for cats instead of just one. It features a different active ingredient, spinetoram, compared to imidacloprid, the main ingredient used in the other Advantage products.

These medications are dosed separately for dogs and cats and given by weight, so it is important to use the correct species and sized medication for your pet. Use only specific Advantage® products as advised by your veterinarian.

Using cat medications on dogs or using dog medications on cats can cause serious problems, including lack of efficacy or an overdose.  

How Advantage®, Advantage® XD Cat, K9 Advantix® II and Advantage Multi® Work in Dogs and Cats

The main ingredient in most of the Advantage line of products is imidacloprid, which works by blocking certain naturally occurring chemicals found in parasites that are responsible for sending nerve signals.

Imidacloprid disrupts their central nervous system and causes death of the parasite. When used as a topical product, imidacloprid does not enter your pet’s bloodstream.

The second active ingredient in Advantage® and K9 Advantix® II products is pyriproxyfen, which mimics a growth hormone that naturally occurs in parasites.

Pyriproxyfen targets young and immature parasites by preventing them from growing into adulthood. It can also prevent egg production in female insects.

K9 Advantix® II also contains a third ingredient, permethrin, which works similarly to imidacloprid. Permethrin blocks certain chemical messengers in ticks and overwhelms their nervous system, causing paralysis and death.

Permethrin is toxic to cats; K9 Advantix® II should never be used in a cat. Cats should not be allowed around dogs treated with K9 Advantix® II within the first 24 hours of application.

Advantage Multi® products contain a second ingredient, moxidectin, which shifts chloride, a naturally occurring electrolyte, across the cell membrane of certain susceptible worms such as heartworms, roundworms, and hookworms.

By overloading chloride into these worms, it affects the electrical activity within their nervous system, causing muscle paralysis and death.

In place of imidacloprid, Advantage® XD Cat uses a single active ingredient, spinetoram, which works by disrupting the flea’s nervous system, thereby causing paralysis and death of the flea.

Advantage®, Advantage® XD Cat, K9 Advantix® II and Advantage Multi® Directions

Follow the directions on the drug label of the species-specific product or as provided by your veterinarian. These topical products should be applied to the skin after the fur has been parted.

In cats and ferrets, medication should be applied to one area at the base of the head. When using K9 Advantix® II, it is applied in 2–3 equal spots along the back, from the shoulders to the tail. Advantage Multi® and Advantage® XD are applied in 3–4 equal spots along the upper back to the base of the neck in areas where your pet is unable to lick.

Advantage® is waterproof after application. If you would like to bathe your pet, it’s recommended to bathe them before application and make sure they are thoroughly dry before you apply Advantage®.

More frequent bathing or swimming may prevent Advantage® from protecting your pet for the full duration of 30 days, or the full 60 days for Advantage® XD for Cats.

Missed a Dose?

If you forget to give a dose of Advantage®, Advantage® XD Cat, K9 Advantix® II, or Advantage Multi®, give it when you remember. Most of these medications are given once a month and the schedule should follow as close to 30 days as possible in between dosages. If your veterinarian has directed you to give this medication on a different dosing schedule, contact them for further instructions if a dose was missed.

Possible Side Effects of Advantage®, Advantage® XD Cat/K9 Advantix® II/Advantage Multi®

Side effects with any of the topical Advantage/Advantix products may include:

Additional side effects that may be seen with Advantage XD/Multi® may include:

Additional side effects that may be seen with Feline Advantage Multi® may include:

  • Lethargy

  • Agitation

  • Excessive grooming

  • Irritation at the application site: scratching, rubbing, or shaking

  • Increased thirst

Human Side Effects

This medication is not for use in humans. It is recommended to wash your hands after administering this medication, as it may be harmful to humans if swallowed or absorbed through the skin. This medication may also cause eye irritation if it gets into the eyes.

Do not allow children to come into contact with animals being treated with these medications until the application area is completely dry. If you accidentally ingest a pet medication, have a skin reaction to this product, or get this product in your eyes, please call your physician or the national Poison Control Center hotline at 800-222-1222.

Monitoring

Aside from generally monitoring your pet after application, no specific monitoring is required for this medication. However, most veterinarians routinely screen for parasites during annual exams.

Call Your Vet If:

  • Severe side effects are seen (see above)

  • Your pet’s condition worsens or does not improve with treatment

  • You see or suspect an overdose

  • You have additional questions or concerns about the use of Advantage®, Advantage® XD Cat, K9 Advantix® II, or Advantage Multi®

Advantage®, Advantage® XD Cat/K9 Advantix® II/Advantage Multi® Overdose Information

Overdose symptoms will depend on which product was used. General symptoms of an overdose may include:

  • Diarrhea

  • Vomiting

  • Decreased appetite

When pets are given this medication orally, the following symptoms may be noted in addition to those listed above:

  • Tremors

  • Lack of coordination

  • Drooling

  • Vomiting

  • Cough

  • Fatigue (lethargy)

If you suspect an overdose, used the wrong product on your pet, or accidentally gave this topical product by mouth, immediately contact your veterinarian, seek emergency veterinary care, or call an animal poison control center. Consultation fees often apply.

Pet Poison Helpline® 855-764-7661

ASPCA® Animal Poison Control 888-426-4435

Advantage® II

Advantage® II is a topical over-the-counter product for the prevention and treatment of all life stages of fleas and lice in canines 7 weeks of age and older and weighing more than 3 pounds. It contains the active ingredients imidacloprid and pyriproxyfen.

Feline Advantage® II

Feline Advantage® II is a topical over-the-counter product for the prevention and treatment of all life stages of fleas in felines 8 weeks of age and older and weighing more than 2 pounds. It contains the active ingredients imidacloprid and pyriproxyfen.

Feline Advantage® XD

Advantage® XD Cat is a topical over-the-counter product for the prevention and treatment of fleas in felines 8 weeks of age and older and weighing more than 1.8 pounds. It contains the active ingredient spinetoram.

Ferret Advantage®

Ferret Advantage® II is a topical over-the-counter product for the prevention and treatment of all life stages of fleas and lice in ferrets 10 weeks of age and older and weighing more than 1 pound. It contains the active ingredients imidacloprid and pyriproxyfen.

K9 Advantix® II

K9 Advantix® II is a topical over-the-counter product for the prevention and treatment of all life stages of fleas and lice in canines 7 weeks of age and older and weighing more than 4 pounds. The addition of the medication permethrin helps repel and kill ticks including Deer, American Dog, Lone Star, and Brown dog ticks. K9 Advantix® II is also labeled to repel mosquitos and biting flies. Do NOT use this product on felines. Keep felines away from dogs treated with this product for 24 hours.

Advantage Multi®

Advantage Multi® is a topical over-the-counter product for the prevention and treatment of all life stages of fleas and lice in canines 7 weeks of age and older and weighing more than 3 pounds. The addition of the medication moxidectin allows this product to prevent heartworm disease and can also treat and control scabies (sarcoptic mange) as well as hookworms, roundworms, and whipworms.

Feline Advantage Multi®

Feline Advantage Multi® is a topical over-the-counter product for the prevention and treatment of all life stages of fleas and lice in felines 9 weeks of age and older and weighing more than 2 pounds. The addition of the medication moxidectin allows this product to treat and control ear mites, hookworms, and roundworms infestations, while also preventing heartworm disease.

Feline Advantage Multi® is also approved for use in ferrets weighing 2–4.4 pounds. The added benefit of utilizing this product in ferrets is to prevent heartworm disease along with the treatment and prevention of flea infestations.

Advantage®/Advantage® XD Cat/ K9 Advantix® II/Advantage Multi® Storage

All Advantage®, Advantage® XD Cat, K9 Advantix® II, and Advantage Multi® products should be stored at controlled temperatures between 39 F and 77 F. Protect from freezing.

Keep the medication in the provided blister packs until ready to use in order to protect from moisture and light. 

Keep out of reach of children and pets.

FAQs

How long does K9 Advantix® II take to work?

On dogs that have been treated with K9 Advantix® II, fleas will start to die within 12 hours of application. New fleas that jump onto your pet will be killed within two hours.

Do you need a prescription for Advantage® II for dogs?

Advantage® II is available over the counter, no prescription necessary. It is important to work with your primary care veterinarian to ensure that your pet is on a parasite prevention program that works best for your pet and the area you live in.

What is the difference between Advantage® and Advantage® II for cats?

Advantage® contains only imidacloprid and is no longer available for sale within the United States. Feline Advantage® II contains imidacloprid and pyriproxyfen, which increases its efficacy against all fleas in various life stages.
 

How long does Advantage® II take to work on cats?

On cats that have been treated with Advantage® II, fleas will start to die within 12 hours of application. New fleas that jump onto your pet will be killed within two hours.

What happens if my cat licks Advantage Multi®?

Drooling and vomiting are the most common symptoms observed after a cat licks a freshly applied area of Advantage Multi®. Multi-cat homes should take care to separate cats until this product has fully dried, which may take up to 24 hours after application.

What is the difference between Advantage® and K9 Advantix® II?

K9 Advantix® II has the addition of the medication permethrin, which allows this product to repel and kill ticks including Deer, American Dog, Lone Star, and Brown dog ticks. K9 Advantix® II is also labeled to repel mosquitoes and biting flies.

No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.

 


Stephanie Howe, DVM

WRITTEN BY

Stephanie Howe, DVM

Veterinarian

Dr. Stephanie Howe graduated from the University of Florida College of Veterinary Medicine in 2011, after receiving a Bachelor of Science...


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