Revolution is a prescription topical medication for cats that prevents and treats several common parasites, including fleas, heartworm, ear mites, roundworms, and hookworms. Made by Zoetis Inc., it’s applied once a month to the skin at the base of the neck and is safe for kittens as young as 4 weeks old.
What Revolution Covers
The original Revolution for cats uses a single active ingredient called selamectin. Applied monthly, it protects against adult fleas and flea eggs, heartworm disease, ear mites, roundworms, and hookworms. That combination of internal and external parasite coverage in one product is what made Revolution popular when it first hit the market, and it remains a go-to choice for indoor and outdoor cats alike.
There’s also an upgraded version called Revolution Plus, which adds a second active ingredient (sarolaner) alongside selamectin. The Plus version covers everything the original does, and adds protection against four types of ticks: the lone star tick, Gulf Coast tick, American dog tick, and black-legged (deer) tick. It also prevents flea tapeworm infections by killing the fleas that carry them. Revolution Plus was the first combination parasite preventative FDA-approved to kill all four of those tick species.
How It Kills Parasites
Selamectin works by targeting the nervous system of insects and parasites. It locks onto specific channels in parasite nerve cells, forcing those channels to stay permanently open. This causes a continuous flood of charged particles into the nerve cell, which shuts down all nerve signaling. Without nerve impulses reaching their muscles, the parasites become paralyzed and die. Because this binding is irreversible, a single dose keeps working for weeks as the medication distributes through your cat’s skin and bloodstream.
Mammals, including cats, don’t have the same type of nerve channels that selamectin targets. That’s why the drug is lethal to parasites but safe for your cat at recommended doses.
Heartworm Prevention
Heartworm disease in cats is harder to detect and treat than in dogs, which makes prevention especially important. In clinical studies, a single monthly dose of Revolution (selamectin at 6 mg/kg) was 100% effective at preventing heartworm development in cats. The medication kills heartworm larvae transmitted by mosquitoes before they can mature into adult worms that damage the heart and lungs.
Even indoor cats can benefit from heartworm prevention, since mosquitoes easily get inside homes. Once adult heartworms establish in a cat, there is no approved treatment to eliminate them the way there is for dogs, so monthly prevention is the only reliable strategy.
Dosing and Application
Revolution is dosed by weight, with pre-measured tubes designed for specific weight ranges. For cats, the standard dose is 6 to 12 mg/kg of body weight. You part the fur at the base of the skull, between the shoulder blades, and squeeze the tube directly onto the skin. That spot is chosen because your cat can’t easily lick it off.
The product is approved for cats and kittens 4 weeks of age and older. It’s applied once every 30 days, year-round in most climates. Because Revolution is a prescription medication, you’ll need a veterinary visit or an existing patient relationship to obtain it. Your vet will confirm the right product and tube size based on your cat’s current weight.
Side Effects
Revolution has a strong safety profile. In FDA clinical trials for both the original and Plus formulations, no treatment-related adverse reactions were reported. Some cats may experience temporary hair loss or mild skin irritation at the application site, and occasional digestive upset has been noted in post-market reports, but these reactions are uncommon.
If you notice excessive drooling, vomiting, or muscle tremors after application, it’s possible your cat groomed the wet product before it dried. Applying it correctly to the base of the skull minimizes this risk. Let the application site dry completely before allowing other pets in the household to groom your cat.
Revolution vs. Revolution Plus
The choice between the two versions comes down to tick exposure and tapeworm risk. If your cat goes outdoors or lives in an area with ticks, Revolution Plus offers broader coverage that the original doesn’t. Indoor-only cats with no tick exposure may do fine on the standard formula, though many vets now default to the Plus version for its added protection against tapeworms and ticks.
Both versions share the same monthly application schedule, the same minimum age requirement of 4 weeks, and the same selamectin base for heartworm and internal parasite coverage. The key difference is that Revolution Plus pairs selamectin with sarolaner, giving it the ability to kill ticks and providing stronger flea activity. Price is typically a bit higher for the Plus formulation, but the gap is modest relative to the expanded coverage.