Advantage Multi for Cats: Dosage, Safety & Side Effects

Share Email Pinterest Linkedin Twitter Facebook

group of cats

Advantage Multi is a brand name for a topical, “spot-on” flea treatment and and heartworm disease prevention product manufactured by Bayer containing the ingredients imidacloprid and moxidectin.

Advantage Multi For Cats Overview

Medication Type:
Macrocyclic lactone antiparasitic
Topical liquid solution
Prescription Required?:
FDA Approved?:
Life Stage:
Cats 9 weeks of age or older and weighing at least 2lb
Brand Names:
Advantage Multi for Cats
Common Names:
Imidacloprid and moxidectin
Available Dosages:
Topical solution: 2-5lb, 5-9lb, 9.1-18lb

This article is primarily focused on the Advantage Multi for Cats product. You’ll learn about Advantage Multi for Cats, its ingredients, the ranges of pests it targets, possible side effects to consider, and some frequently asked questions.

You can also find an article on the product Advantage II for Cats, as well as an article encompassing a broader overview of Advantage products for cats.

About Advantage Multi for Cats

Advantage Multi’s main ingredients are imidacloprid and moxidectin, which work in combination to kill adult fleas, mosquito-borne heartworms, intestinal roundworms and hookworms, and ear mite infestations.

Also Read: How To Get Rid Of Fleas On Your Cat

Advantage “spot-on” products are applied to the surface of a small target area or “spot” of the skin, usually in front of the shoulders at the back of the neck.

Advantage Multi collects in the oils of the skin and hair, allowing for continual release, lending to its 30 day period of efficacy for cat fleas. Per the product label, it can start killing fleas within 2 hours and can kill all adult fleas within 12 hours.

The moxidectin in Advantage Multi is absorbed systemically, which is necessary for its effects against heartworms, intestinal parasites, and ear mites.

It is important to note that while fleas are affected by Advantage Multi by coming in contact with the skin and don’t have to actually bite a kitty to die, Advantage products for cats do not provide true repellency that would prevent fleas or ticks from coming in contact with a pet.

While Advantage Multi does prevent mosquito-borne heartworm disease, it is also important to note that Advantage Multi does not repel or kill mosquitos themselves.

What Does Advantage Multi Do for Cats?

Advantage Multi contains imidacloprid and moxidectin. Imidacloprid works fast to kill fleas by acting on nicotinic acetylcholine receptors of the central nervous system, essentially causing paralysis and death of the flea.

The addition of moxidectin provides a spectrum of action against ear mites, the mosquito-borne heartworm Dirofilaria immitis, and two intestinal parasites: the roundworm Toxocara cati and the hookworm Ancylostoma tubaeforme.

Moxidectin largely acts to kill nematodes (worms) and arthropods (fleas and mites) by inhibiting the electrical activity of their nerve cells and muscle cells.

Unlike Advantage II, Advantage Multi does not contain pyriproxyfen, so it is not effective against flea eggs and larvae, only adult fleas.

Side Effects of Advantage Multi for Cats

cat receiving flea drops on her back

Side effects of using Advantage Multi are generally uncommon, but when occur include behavioral changes like agitation, excessive grooming, hiding, and pacing.

When used properly, side effects to Advantage Multi for cats are uncommon. Advantage Multi is only labeled for cats at least 9 weeks of age and at least 2lb in weight. Topical products like Advantage should never be ingested.

According to the product label for Advantage Multi, the most common side effects, though generally uncommon at about 8% of those studied, include behavioral changes like agitation, excessive grooming, hiding, and pacing.

Signs of discomfort like skin irritation, head-shaking, and scratching at the application site are the next most common but still rare at about 4% of cats.

The manufacturer also reports that lethargy can be seen with a cat appearing really tired. This has been noted rarely at about 3% of cats, but more often in geriatric cats or those with other underlying disease conditions.

Imidacloprid and moxidectin as found in Advantage Multi are generally quite safe, even if a little is accidentally ingested.

However, the products are very bitter tasting. If a kitty were to lick recently applied Advantage Multi off either themselves or a housemate, the bitter taste alone can lead to excessive drooling, agitation, and sometimes even vomiting.

According to DVM360’s article “Toxicology Brief: The 10 most common toxicoses in cats” this effect is typically not a true toxicity, but a sometimes dramatic reaction to the bitter taste. Providing milk or liquid from a tuna can help resolve the signs in short order.

To avoid this from happening, it is important to apply any topical flea/tick product to the skin in front of the shoulder blades at the back of the neck, a location even the most flexible cat cannot reach to lick. In multiple cat households where lots of co-grooming occurs, separating housemate kitties for up to 24 hours after application to allow the product to fully dry may be advisable.

Although Advantage Multi products for dogs and cats contain the same active ingredients, the manufacturer does not advise using a dog product on a cat, even if they are similar in weight. Sometimes, there are differences in the inactive ingredients between dog and cat products that would make them inappropriate to consider interchangeable.

Using Caution With Other Flea/Tick Products

owner applying flea treatment on cat

If for some reason you are unsure if the product was administered correctly or whether all of it was applied, it is usually safest to not apply an additional dose.

While Advantage Multi for Cats has been established as a safe product, the active ingredients may be found in other products in combination with other ingredients that are not safe for cats. This is especially the case with dog products like K9 Advtantix II, which has a similar name and similar-appearing packaging. K9 Advantix II contains permethrin, which is extremely toxic to cats.

Also Read: Flea And Tick Medication Poisoning In Cats

Fortunately, these products are now required to include a warning against use in cats. But just to be safe, when selecting a flea/tick product for your kitty, always make sure the product includes a picture of a cat and indicates the product is specifically for cats.

It is also always advisable if you have a pup and kitty who like to hang out together or groom each other, to separate them for 24 hours after applying a topical product to your dog, especially if the product contains permethrin.

If you have any concerns for potential toxicity, even if you think your kitty might have just licked some Advantage Multi off her fur and is having a bitter taste reaction, it is always best to contact your veterinarian, or the ASPCA Animal Poison Control Center for further advice.

And lastly, topical products like Advantage Multi have been known to cause skin and eye irritation in people. It is best to avoid contact with the solution during application and to wash your hands after.

Advantage Multi for Cats Dosage

Advantage Multi is typically applied every 30 days for the best protection.

Always follow all instructions on the packaging for any topical solution product you use for your kitty. Advantage vials have a cap that needs to first be removed.

How to Apply Advantage Multi for Cats

The tip of the cap is then inserted onto the tip of the vial and twisted to break the seal. The contents of the vial can then be applied by parting the fur and applying to the skin along the back of the neck in front of the shoulders where a kitty cannot reach to lick it off of himself.

While Advantage products are considered to be waterproof, make sure not to bathe your kitty for at least 24 hours after an application. Bathing shortly before application may also reduce its effectiveness.

If for some reason you are unsure if the product was administered correctly or whether all of it was applied, it is usually safest to not apply an additional dose.

If you have any questions about application or safety for Advantage products or any topical product, make sure to get in touch with your veterinarian.


Advantage Multi for Cats can be effective at treating and eliminating certain parasitic pests for your kitty. They are also relatively safe when used properly.

Topical products like Advantage Multi can all have different combinations of ingredients targeting different parasites, which can sometimes be confusing. Make sure to clarify any questions you have about the best product for your kitty by having a chat with your vet.

Also Read: Advantage II For Cats: Dosage, Safety & Side Effects

Frequently Asked Questions

Does Advantage Multi for Cats Require a Prescription?

Yes, Advantage Multi is the only Advantage product that requires a prescription approved by a licensed veterinarian, owing to it being a heartworm preventative.

Generally, it is advised that a pet be confirmed to not have an active heartworm infection prior to being put on a heartworm prevention product. This is because in some pets, adverse reactions have been seen when a heartworm positive pet is started on a prevention product. 

This does not happen in all pets, but a reaction can occur to the adult heartworms being acutely affected by the active ingredients in the heartworm preventative medication. This is one reason yearly blood screening for heartworm disease is required for dogs.

Although yearly screening for heartworm is recommended in cats, especially for cats who spend time outdoors, the antigen test can only detect about half of cats truly infected with heartworm. However, a veterinarian should still be assessing a cat’s risk and safety for starting a heartworm medication, especially if a cat could be showing signs of active heartworm infection.

According to the manufacturer, when applied to cats actively infected with heartworm, no cats showed adverse effects in studies. This does support that moxidectin is a safe product, but as it is absorbed systemically, a cat should still be considered healthy by an attending veterinarian before starting it.

What Does Advantage Multi for Cats Treat?

Advantage Multi’s main ingredients are imidacloprid and moxidectin. Imidacloprid affects the nervous system of a flea, quickly killing adult fleas. 

Moxidectin works by inhibiting the electrical activity of nerve cells in nematodes like roundworms, hookworms, and heartworms, and inhibiting electrical activity in muscle cells in arthropods like fleas and mites.

How Long Does It Take for Advantage Multi for Cats to Work?

Within about 24 hours, the ingredient imidacloprid is carried by oils in the skin to protect the entire body of a cat against fleas. The slow release of the ingredients in skin oil secretions also allows for the 30 days of efficacy against fleas. 

According to the manufacturer, Advantage Multi can begin killing fleas within 2 hours of application with all adult fleas being killed within 12 hours.

Moxidectin is absorbed systemically by the body reaching peak levels within 1-5 days of application. Moxidectin maintains its effective concentrations in the body for about 30 days. 

Is Advantage Multi Safe for Cats?

Advantage Multi is considered safe for cats as long as the cat-only product is used and applied properly. While a hypersensitivity or allergic response to one of the ingredients is possible, this is very rare and most cats tolerate Advantage Multi quite well.

Not all, but most cases of topical flea/tick product reactions or adverse effects in cats come from either an improper product being used, or the proper product not being applied correctly.

Topical application products like Advantage Multi are not meant for oral ingestion, and should be applied in front of the shoulders on the back of the neck where a kitty is least able to reach to lick. Application elsewhere on the body can provide an opportunity for a fastidiously grooming kitty to lick off and ingest the product.

According to the manufacturer, all cats studied who ingested a full dose of the product developed hypersalivation, vomiting, and poor appetite for at least one day, highlighting the importance of applying it correctly.

In multiple pet households where housemate cats or dogs may lick or groom each other, it may be advisable to keep them separate from each other for 24 hours after application of a topical treatment product to allow the product to fully disperse and dry. This is especially true if a product containing permethrin is applied to a dog in a household also containing cats.

Although changes in product labeling requirements have made things better, there can sometimes be confusion among pet parents when choosing products to apply, especially in homes with both dogs and cats. 

The K9 Advantix II products and Advantage products for cats have very similar-sounding names and similar-looking packaging, but they contain different ingredients. K9 Advantix II contains permethrin, which is very toxic to cats. 

Always make sure the product you purchase has a picture of a cat on it and says that it is specifically used for cats. Product packaging is now required to have this information to help avoid confusion. Products like K9 Advantix II are also required to have a warning label against use in cats. If you have both canines and furry felines and both types of products at home, always make sure to double check which box you get the medication out of before applying it.

Help us do better! Was this article helpful and relevant?
What can you say about this article?
I am completely satisfied, I found useful information and tips in this article
Article was somewhat helpful, but could be improved
Want to share more?
Thank You for the feedback! We work to make the world a better place for cats, and we're getting better for you.
Avatar photo

About Dr. Chris Vanderhoof, DVM, MPH

Dr. Chris Vanderhoof is a 2013 graduate of the Virginia-Maryland College of Veterinary Medicine (VMCVM) at Virginia Tech, where he also earned a Masters in Public Health. He completed a rotating internship with Red Bank Veterinary Hospital in New Jersey and now works as a general practitioner in the Washington D.C. area. Dr. Vanderhoof is also a copywriter specializing in the animal health field and founder of Paramount Animal Health Writing Solutions, which can be found at Dr. Vanderhoof lives in the Northern Virginia area with his family, including 3 cats.