3 Best Heartworm Medications for Cats in 2026, Recommended by Vets
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Heartworm disease in cats is a potentially fatal condition that affects the heart, lungs, and blood vessels. It’s caused by a parasite spread by mosquitoes, and while cats are not a natural host for heartworms, serious infections can pose a danger to cats.
The best heartworm medicine for cats is safe, reliable, easy to administer, cost-effective, and offers protection against a variety of parasites.
To help you narrow down the choices between the available cat heartworm pills, chews, and topicals, we asked our panel of veterinarian experts to share their top picks for the best heartworm medicine for cats.
What to Consider When Buying Heartworm Medicine for Cats
These important factors can help you make the right decision when choosing the best heartworm medication for your cat.
Your Vet’s Input
When selecting the right heartworm medicine for cats, the best place to start is with your vet. All heartworm medications for cats must be prescribed by a veterinarian. Your vet can help you choose which approach works best for your own cat’s age and lifestyle.
Lifestyle and Exposure Risk
Outdoor cats, particularly those living in warmer, mosquito-prone climates, have a higher risk for heartworm disease. But indoor cats are susceptible as well.
Mosquitoes can easily enter the home, and it only takes one bite to potentially cause harm. For this reason, vets recommend all cats and kittens, even indoor-only cats, be on year-round, cat-specific heartworm prevention medication.
Your Cat’s Age and Weight
Most heartworm medicine for cats is formulated for specific age and weight ranges, so always follow the manufacturer directions and your veterinarian's recommendations. Many kittens can start taking heartworm preventives as early as 8 weeks of age, but always get your vet's approval first.
Method of Administration
Heartworm prevention for cats is available in oral or topical forms, typically given monthly. There is currently no FDA-approved injectable heartworm medicine for cats like there is for dogs. Oral medications can be a good option for food-motivated cats, while topical treatments are ideal for cats who are finicky about pills or treats.
Ultimately, the best heartworm preventative for cats will be the one your cat will consistently accept.
Spectrum of Parasite Protection
Heartworm medication often protects against a wide variety of pests including fleas, ticks, and several types of intestinal worms beyond heartworm, such as whipworms, roundworms, and hookworms.
If your cat isn't currently taking another parasite preventative, a broad-spectrum product may be the most convenient option. If they're already on flea and tick prevention, talk with your veterinarian about choosing a heartworm medicine that complements their current regimen.
How We Chose the Best Heartworm Prevention for Cats
This list of the best heartworm prevention in cats was meticulously curated by a panel of veterinarians and veterinary technicians who are employed by Chewy, the publisher of PetMD. They were asked to choose the best heartworm prevention for catsin their honest opinion, across multiple categories based on the following:
- Popularity with pet parents
- Cost
- Availability
- Food & Drug Administration (FDA) approval
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 in Vet Verified articles or exert influence on our panelists as they evaluate products. Our sole goal with this program is to provide you with the information you need to make the best decision for your pets.
The Best Heartworm Prevention in Cats FAQs
How do cats get heartworm disease?
The simplest explanation is that cats contract heartworm when bitten by a mosquito that is carrying the larvae of a parasite called Dirofilaria immitis. A more detailed explanation includes a complex heartworm lifecycle that involves many immature and adult phases.
Once they enter through a bite mark, the worms make their way to your cat’s bloodstream and pulmonary arteries, wreaking havoc on their respiratory system. Heartworm disease in cats can cause lung disease, chronic coughing, and even sudden death.
Is heartworm curable for cats?
There is currently no treatment for heartworm disease in cats. Infected cats are at increased risk for permanent cardiovascular and respiratory disease, which makes year-round heartworm prevention for cats important for indoor and outdoor cats.
Should cats take heartworm prevention?
Yes, all indoor and outdoor cats should receive heartworm prevention medication. With several chewable and topical options available, finding the best option for your cat will ensure you’re able to consistently administer reliable protection from heartworm and other parasites. Only give heartworm medication that’s been FDA-approved for cats or kittens and be sure to consult your vet about the appropriate dosage for their age and weight.