7 Best Heartworm Preventative Medications and Products for Dogs in 2025, Recommended by Vets
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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 is a serious disease caused by internal worms growing inside a dog’s blood system and heart, spread by a mosquito bite. Heartworm disease can lead to coughing, shortness of breath, and more seriously, high blood pressure and heart failure.
If your dog contracts heartworm disease, it can be expensive and time-consuming to treat. Canine heartworms can impact dogs in any state, no matter the location, and the number of dogs currently affected by the infectious disease has risen to roughly a million across the United States.
Everything Our Vets Recommend
The dangers of contracting heartworms, the complex treatment process, and the high cost of treatment make heartworm prevention the safest form of defense against the disease.
Whether you’re searching for cost-effective prevention or medications that are combined with other preventatives, the best heartworm medicine for dogs won’t just prevent pups from contracting a dangerous disease, but they also provide pet parents with peace of mind and protect savings accounts from a big hit.
Talk with your vet to determine how you can best protect your pup by taking preventative measures against heartworms.
All heartworm prevention requires an up-to-date heartworm test on file, so you won’t be able to snag the best heartworm for dogs without a vet prescription. And remember, heartworm medication only works when given as directed.
Our Vet Pick: Best In Show
Interceptor Plus Chew for Dogs is our vets’ pick for the best heartworm medication for dogs. This tasty chew is made using real chicken, so even picky pups may struggle to sniff out the medication hidden inside.
Our vets like this dog heartworm medicine the best because it can provide monthly protection against more types of internal parasites than other formulas on this list, including roundworm, hookworm, whipworm, and tapeworm infections. This added defense is great for pups who spend their free time at dog parks. Our vets also like that this option is only needed once a month and is suitable for all dog sizes.
This product contains two medicines, known as anthelmintics, that offer protection from heartworm infections. Milbemycin oxime can bind to chloride in parasites to kill them, and praziquantel controls heartworms by breaking down the skin of the parasite enough to be taken care of by a dog’s immune system.
- Administered once per month, ideally on the same day
- FDA-approved
- More intestinal parasites covered than other heartworm preventatives on this list
- Small dogs and puppies over 2 pounds can also use it
- Possible side effects may include: vomiting, diarrhea, and depression/lethargy
Our Vet Pick: Best Topical
Topical heartworm preventatives are another common way of administering protection to your pooch. For the best dog heartworm prevention that can be applied topically, our vets recommend Advantage Multi for Dogs.
This monthly solution protects against heartworms, fleas, roundworms, hookworms, whipworms, and sarcoptic mange. The active ingredient, imidacloprid, kills fleas through direct, physical contact, so they don't have to bite your dog to die.
In a controlled study funded by the manufacturer, the combination of imidacloprid and moxidectin found in Advantage Multi Topical Solution was shown to be capable of preventing heartworm infection and disease for the entire month it was used. Our vets like that these ingredients work against microfilaria, or baby/larval heartworms, as well.
- FDA-approved
- Monthly solution for pets who don’t love taking chews
- Pet parents need to limit interactions with other pets, especially cats, for 24 hours after application
- May present a strong odor for the first 24-48 hours
- Not ideal for dogs who are bathed frequently
- Possible side effects may include: localized itching, lethargy, and/or inappetence
Our Vet Pick: Best Chew
If your dog requires something tasty to keep them healthy, Heartgard Plus Chew is the top pick, according to our vets.
Picky pups may even enjoy this preventative because of its real-beef taste. The manufacturer recommends this chew be fed in a manner to encourage chewing, so try to avoid letting your dog swallow the chew whole.
Pet parents will find a combination of ivermectin to sterilize adult heartworms and kill microfilaria, and pyrantel to treat and control hookworms and roundworms by paralyzing worms, which are then expelled from the body in feces.
- One of the most palatable chews available
- Suitable for dogs of any size over 6 weeks of age
- Beef flavoring additive (not ideal for dogs with certain food allergies)
- Possible side effects may include: depression/lethargy, vomiting/anorexia, and/or diarrhea
Our Vet Pick: Best Budget
Eliminating heartworms doesn’t have to break the bank. Our vets chose Iverhart Max Chew for pet parents looking for a potent, cost-effective heartworm option. These monthly chews have a bacon flavor to entice pups to eat them.
Iverhart Max Chew for Dogs contains a potent combination of ivermectin, pyrantel pamoate, and praziquantel. These ingredients work together to provide a broad spectrum of protection against heartworm disease, roundworms, hookworms, and tapeworms.
- FDA-approved
- More cost-effective compared to other options on this list
- Potentially less appealing to picky eaters
- Chew can’t be split
- Possible side effects may include: depression/lethargy, vomiting/anorexia, and/or diarrhea
Our Vet Pick: Best All-in-One (Heartworm, Flea, and Tick)
Simparica Trio Chewable Tablet for Dogs is our vets’ pick for the best flea, tick, and heartworm prevention for dogs. While no preventative medication is truly “all-in-one,” this multi-coverage option covers more ground than most other medications on the list.
Each monthly chew contains sarolaner, which is distributed through your pooch, killing ticks and fleas when they bite. The chew also contains moxidectin to treat intestinal parasites and pyrantel to treat and control hookworms.
Our vets say this product is a great option for pet parents looking for a preventative medication that goes beyond heartworm and also helps combat fleas, ticks and many intestinal parasites.
They also like that puppies over 8 weeks old and weigh 2.8 pounds can start this monthly medication and continue it for life. While the tablet is chewable, you may need a pill pocket to persuade your pup to eat it.
- FDA-approved
- Kills five types of ticks
- Multi-coverage includes not only heartworm, but other types of parasites
- May be easier to administer with a pill pocket
- Pricier than other options on list due to increased parasite coverage
- FDA-approved
- Possible side effects may include: vomiting, diarrhea, and/or lethargy
Best All-in-One (Runner-Up)
Our vets selected NexGard PLUS Chew as our runner-up for pups with an up-to-date heartworm test.
This new FDA-approved product can prevent heartworm disease when given as directed, kill adult fleas before they lay eggs, and treat hookworms and roundworms.
The key ingredients are afoxolaner, which is effective in fighting fleas and ticks, and milbemycin oxime to fight heartworms by shifting chloride inside parasitic worms to kill them.
- FDA-approved
- Protects against three species of hookworms, two species of roundworms, and four species of ticks
- Does not protect against tapeworms
- Possible side effects may include: diarrhea, vomiting, and/or lethargy
Best For Puppies
Revolution Topical Solution is our vet’s pick for the best heartworm prevention for puppies.
Every chew contains selamectin to fight heartworms, butylated hydroxytoluene, and isopropyl alcohol to promote absorption through the skin.
Our vets like that this product can be used on puppies as young as 6 weeks old no matter how much they weigh, which means even the smallest breeds can use it. Additionally, it can be a useful product for picky eaters because it is a topical solution.
- FDA-approved
- Can be administered to puppies 6 weeks and older
- Only formulated to protect against one type of tick
- Possible side effects may include: vomiting, diarrhea, and/or anorexia (decreased appetite)
