The 6 Best Heartworm Medications for Cats, Recommended by Vets in 2025
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All products in this article have been reviewed by our trusted vets and experts. PetMD is owned by Chewy.
Heartworm disease in cats is a potentially fatal condition caused by a parasite that lives in a cat’s tissues and blood vessels. Unlike heartworm disease in dogs, cats are not the natural host for heartworms. Still, serious heartworm infections pose a danger to cats.
Fortunately, heartworm disease in cats can be easily prevented with a simple monthly heartworm medication.
How Do Cats Get Heartworm Disease?
The organism that causes heartworm disease in cats and dogs is a worm, Dirofilaria immitis. The disease is spread when mosquitoes bite infected cats and transfer the larvae (called microfilaria) to a new kitty host.
Once the microfilaria have infected a new host cat, the parasite goes through a complex lifecycle. It first lives in the host cat’s tissues, then matures as it moves into the bloodstream, where it causes significant inflammation. Adult heartworms eventually travel to the pulmonary arteries, which bring blood from the heart to the lungs.
Once in the pulmonary arteries, some of the adult worms die. This provokes a strong immune response that can lead to severe lung disease and in some cases be fatal.
Currently there is no treatment for heartworm disease in cats. Infected cats are at increased risk for permanent cardiovascular and respiratory disease. Because of this risk, heartworm prevention is important even for indoor cats that hardly ever or never go outside.
The best way to protect your cat from heartworm disease is by ensuring they are on routine monthly heartworm prevention all year long. In this article, our panel of veterinarians shares their recommendations for the best heartworm medication to protect your cat.
Heartworm Medicine for Cats: What to Look For
When selecting the right heartworm medication for your cat, the best place to start is with your vet. All heart medications for cats must be prescribed by a veterinarian. Your vet can help you choose which approach works best for your cat’s age and lifestyle.
Options include topical treatments that are applied directly to the cat’s skin, usually between the shoulder blades, and chews that are given along with food or in pill pockets. Both topical and chew options are generally given monthly.
Our panel of veterinarians reviewed a variety of products that are available in different applications. Increasingly, vets are turning to combination products that protect against a wide variety of pests, including heartworms, whipworms, roundworms, hookworms, and fleas and ticks, so many of the products target a variety of parasites at once.
How We Evaluated These Products
To help you choose the best heartworm medication for your cat, we asked a group of Chewy vets and animal health experts to offer their unbiased clinical opinions on leading products.
Combined, our panel has decades of collective experience using and recommending flea, tick, and intestinal worm prevention medication in clinical practice. The products reviewed in this article were selected based on a few factors:
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Popularity with pet parents
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Cost
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Availability
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Food & Drug Administration (FDA) approval
The panel evaluated each product on several parameters, including their clinical and real-world experience, application method, formula and ingredients, effectiveness, cost, and which parasites they target.
The opinions and product recommendations in this article belong solely to the review panel of veterinarians and animal health experts. Manufacturers and vendors cannot pay for placement or exert influence on the product reviews that appear in articles with the Vet Verified badge. Our sole goal with this program is to provide you with the information you need to make the best decision for your pets.
