Best Heartworm Prevention for Dogs: Prevent Worm Development With These Medicine Approved for Fogs

Wyatt Robinson
Written by Wyatt Robinson

We all know that heartworms can cause serious health complications in dogs. If left untreated heartworm larvae can lodge in the heart lungs and blood vessels and then begin reproducing. Dogs infected with heartworms can develop cough, suffer from blood loss and even die and it only takes a mosquito bite to get our pooch infested. Won’t it be nice if there are medications that can help prevent heartworm infestation in dogs?

Luckily, the cost of best heartworm prevention for dogs is less than what you would spend for your weekly Starbucks coffee. There are pills, topical medication and injectables that can help prevent heartworm infestation in dogs. We all know how expensive vet bills can be and investing in heartworm prevention can help reduce your pet expenses.

Young woman petting her dog

The best heartworm prevention for dogs is hard to choose because there are too many products available in the market. The selection process is confusing because there are too many forms,  ingredients and parasites to look out for. The best way to proceed when you’re looking for heartworm preventive medication is to consult your veterinarian because they can prescribe the correct medicine for your dog.

In this article, we have provided a guide that will help you shop for the ideal heartworm treatments. Also, we have reviewed a number of products which should help you decide in the end. Let’s get to it!

Product NameMinimum Age/WeightDosageAlso Effective Against Price
RevolutionAt least 6 weeksOnce monthlyFleas, American dog tick, ear mites and sarcoptic mangeCheck price on Petcarerx
Sentinel Spectrum6+ weeks of age, weighing 2+ lbsOnce monthlyWhipworms, hookworms, roundworms and tapewormsCheck price on Petmeds
Tri-Heart PlusAt least 6 weeksOnce monthlyHookworm and roundwormCheck price on Petcarerx
Sentinel4+ weeks of age, weighing 2+ lbsOnce monthlyAdult roundworms, adult hookworms, whipworms, flea eggsCheck price on Petmeds
Heartgard Plus ChewablesAt least 6 weeksOnce monthlyHookworms and roundwormsCheck price on Petcarerx
Trifexis8+ weeks of age, weighing 5+ lbsOnce monthlyHookworm, roundworm, and whipwormCheck price on Petmeds

Things to Consider Before Buying

When shopping for canine heartworm prevention products, here are the things that you should take into account.


Heartworm preventive medication takes many forms. Some of the most common forms are chewable tablets, shots and topical medication. Medicine comes in different forms to make it easier for pet owners to administer the dosage to their dogs.

Image shoawing Heartgard Plus 6 Month Supply on a table

Before buying the medicine, consider your dog’s behavior. If he is the type to avoid injections, it is perhaps best to stick to chewable tablets. There are also dogs that are picky eaters and avoid strange flavors so perhaps topical medicine is their best option.


Many pet parents lead busy lives. And although we always want the best for our best friends, we cannot be there all the time to administer the medicine when it is needed. When it comes to dosage you want something that is easy to administer.

The most recent advance in heartworm prevention is the once-a-year Heartworm Prevention injection.

Try to look for medicine that is effective up to one month. Many chewable tablets offer this kind of convenience so you can just enter the reminder in your smartphone so that you don’t forget. Daily administration of the dosage can be inconvenient especially to busy pet owners.


The type of active ingredient can help determine the effectiveness of your heartworm medication. Knowing the ingredients of your medicine can also prevent possible complications especially if your dog is allergic to some medicine or if it counteracts medicine that they are currently taking. Talk to your veterinarian regarding your dog’s allergies and current medications.

heartwormprevention medicine for dogs

Some of the most popular active ingredients for heartworm prevention include Ivermectin, a popular anti-parasitic that is used to prevent heartworms, head lice, scabies and other infections. Moxidectin is also popular that is used to control heartworms and intestinal worms while Selamectin is also effective against fleas, ear mites, sarcoptic mange. It makes sense to purchase a product that can kill or is effective against more than 1 type of parasite.

Age and Weight of Dog

Weigh your dog before buying any heartworm prevention product. Most medicine manufactured today is for a specific weight or age of dog. Giving your dog medicine without knowing their age or weight can cause fatalities. For example, giving 1 whole chew to 6 week old puppy can cause overdose. Weighing your dog and reading the label can help prevent these fatal mistakes.

Beagle dog laying on grass

Knowing their age and weight will also make it easier for you to know how much medicine to give your dogs. Generally speaking the heavier the dog the more medicine is required. This is especially true if the medication is in powder form. If you give a big dog a small amount, the medicine’s efficacy is decreased and puts your dog in risk of heartworm and other parasites.


One of the best reasons to give dogs heartworm prevention medicine is to avoid an infection. Vet bills can be expensive but so can preventive medicine. As pet owners it is our responsibility to provide the best for our best friends. However, expensive medication can also put a dent on your household budget.

Don’t just settle for the most expensive product in the market or the cheapest. Expensive does not necessarily mean the best and cheap is sometime synonymous to ineffective.

Zoetis Revolution Rx For Dogs and cats

Instead of thinking about the cost, take a look at the ingredients to see if they have the correct amount of active ingredient that makes it effective. You should also consider its efficacy against other parasites. The more types of parasites it kills, the better it is for you and your dog budget-wise.

Veterinarians have good recommendations for heartworm medicine since most of them can only be obtained through prescription. However, doing some research is always helpful especially if you want to be well-informed.

Best Products on Today’s Market

Another good way of becoming well-informed is by reading reviews of heartworm medication. The experience of other pet owners can give you valuable insight and can help you decide if the medicine is the best one for your dog. Here are some of the best heartworm medicines available today.

Revolution Revolution

Price: Approx. $39.98

Dosage: Once monthly

Age and weight: At least 6 weeks

Features: Topical treatment containing Selamectin, quick drying, non-greasy

Best use: Treatment of heartworm, fleas, American dog tick, ear mites and sarcoptic mange

Description: Revolution is a topical ointment administered once a month to control heartworm infestation. It is also effective against fleas, American dog tick, ear mites and sarcoptic mange. This broad-spectrum topical parasiticide is quick drying and non-greasy so your dog does feel sticky after you administer the medicine. It is a once monthly spot-on treatment to prevent internal and external parasites from harming your pet.

As a heartworm prevention medication, Revolution is FDA approved and safe for use. You just apply it on the base of your dog’s neck for month-long protection. As the medicine seeps into your pet’s skin, it distributes the medication providing lasting protection against different kinds of parasites. This is a good product if you’re looking for heartworm prevention medicine. It is well tolerated by dogs with less than 1% displaying symptoms.

However, there are some side effects you need to know about before administering this product. There are pets that exhibit excessive drooling, rapid breathing, hair loss and irritation. Consult your veterinarian if your dog exhibits any of these side effects.

Overall, this is a good product for your dog. It does not only prevent heartworms but also other parasites like fleas and ticks. It can also help control sarcoptic mange which can be very painful to dogs. Dog owners can choose to give their pets the ointment all year-round or only administer during mosquito season.


  • Affordable
  • Fast drying and non-greasy formulation
  • Effective against other parasites


  • Some reported allergic reactions to the product that cause excessive itching

Related: Ticks can enter your house but you can protect it by using Vet’s Best Natural Flea and Tick Home Spray. This is a good complement to Revolution as it can kill ticks in beddings, surfaces, upholstery and carpets.

Check the price on Petcarerx

Sentinel Spectrum Sentinel Spectrum

Price: Approx. $46.56

Dosage: Once monthly

Age and weight: 6+ weeks of age, weighing 2+ lbs

Features: Beef-flavored chewable to protect against 6 parasites, treats and controls whipworms, hookworms, roundworms and tapeworms

Best use: Prevention of heartworm, fleas and intestinal parasites

Description: Dogs will love the delicious beef flavor of Sentinel Spectrum chewables. It contains 3 active ingredients: Milbemycin oxime, lufenuron, and praziquantel that helps to control heartworms, fleas and major intestinal worms. It also contains an insect growth regulator (IGR) that kills flea eggs that prevents larvae from developing into adult fleas.

A box of Sentinel Spectrum contains 6 chewable tablets that can be given to your dog once a month as a treat or you can mix it in with their dog food. The dose is administered orally and is based on your dog’s weight. Once your dog has ingested the product, it works be repelling mosquitoes every month. It is best to give the chews every 30 days to ensure continued protection.

Weigh your dog properly before administering the product. Sentinel Spectrum manufactures their products according to weight so you need to buy accordingly. For example, puppies are given 1 chew every month and you need to buy the green box (for 8.1-25 lbs) while big dogs are also given 1 chew every month but you need to buy the blue box (50.1-100 lbs). To ensure efficacy of the product, it is best to give it with their meals or immediately after the meal.


  • Easy to administer
  • Controls 6 parasites and fleas
  • Good flavor


  • Cannot be given to dogs if they are on amiodarone, cyclosporine , anti-fungals, diltiazem, erythromycin, quinidine, spironolactone, tamoxifen, and verapamil

Related: Some dogs are hypersensitive to medication. For owners wanting natural flea control, try the Safari Flea Comb. Its double-row teeth can get rid of fleas and debris on your dog’s coat while making them look well-groomed.

Check the price on Petmeds

Tri-Heart Plus Tri-Heart Plus

Price: Approx. $24.71

Dosage: Once monthly

Age and weight: At least 6 weeks

Features: Contains Ivermectin and Pyrantel pamoate

Best use: Prevention of heartworm, hookworm, roundworm

Description: Tri-Heart Plus is flavored like beef so your dog does not know that they are taking medicine. Administer once a month to prevent heartworm, hookworm and roundworm infestation. This product is the generic version of Heartgard Plus, making it a more affordable and effective treatment against parasites.

Tri-Heart Plus is good value for money and is FDA-approved. It combines preventive heartworm medicine with an intestinal de-wormer. It is effective in killing immature heartworm and intestinal worms. The beef taste of the product makes it easy to give to your dog. Remember to administer the product the same time each month for ongoing protection. Many past users of Heartgard Plus are using this product because it offers the same protection but with more savings.

It is safe to use for dogs 6 weeks and older. Manufacturers recommend dog owners to read the label before administering the product. Dogs also need to be de-wormed before they can take Tri-Heart Plus. Consult your doctor if your dog experiences side effects such as anorexia, ataxia, convulsions, depression, diarrhea, hypersalivation mydriasis, staggering, and vomiting.


  • Very affordable
  • Beef flavor makes it easy to administer


  • Reports by past users commenting that the product is not very chewable

Related:  Help your dog rest and recover after a bout of heartworm with the Orthopedic Pet Bed from FurHaven. Aside from rest, it helps promote better sleep while supporting the joints in older dogs.

Check the price on Petcarerx

Sentinel Sentinel

Price: Approx. $37.64

Dosage: Once monthly

Age and weight: 4+ weeks of age, weighing 2+ lbs

Features: Flavored tablet contains milbemycin oxime that kills tissue-stage heartworm larvae

Best use: Prevention of heartworm, hookworm, roundworm, and whipworm infestations

Description: Sentinel is a monthly oral medication that helps to prevent heartworms, adult roundworms, adult hookworms, whipworms, and kills flea eggs. It contains milbemycin oxime that prevents the development of parasitic larvae and lufenuron that prevents flea eggs from hatching or maturing into adults. It is FDA-approved and comes in beef flavored tablets.

The product contains milbemycin oxime, a heartworm preventive ingredient so it requires prescription from your veterinarian. It is very easy to administer. Many dog owners give them as treats others put mix it in with their dog food. It is important for dog owners to administer the product regularly (i.e. every 30 days) for continued protection.

Overall, it is a good product if you need heartworm prevention medicine for your dog as it is effective. It also protects against other intestinal worms and kills flea larvae. However, it does not kill adult fleas or ticks. If your dog has adult fleas or ticks, you need to purchase other products to help combat these problems.


  • Effective against heartworm and intestinal worms
  • Easy to adminster


  • Does not kill adult fleas
  • Does not kill or repel ticks

Related: Solve your flea and tick problems with Bayer’s Seresto Flea and Tick Collar. It is water resistant and odor-less and kills and repels fleas and ticks on contact.

Check the price on Petmeds

Heartgard Plus ChewablesHeartgard Plus Chewables for Dogs 

Price: Approx. $29.75

Dosage: Once monthly

Age and weight: At least 6 weeks

Features: Beef flavored chewables with Ivermectin and Pyrantel

Best use: Prevention of heartworm, hookworms, and roundworms

Description: One dose of Heartgard Plus Chewables will keep your dog heartworm-free for a month. This FDA-approved is a trusted medication that does not only deal with heartworms but it also helps to eliminate hookworms, and roundworms. This beef flavored chewable tablet is deadly for parasites and safe for your dog.

Heartgard Plus can be administered all year round or only during mosquitoes-season. Aside from beef, it is also available as an unflavored chewable tablet. Dog owners should note that the product should not be swallowed whole but broken down to prevent choking and for better efficacy.

Your dogs should be tested for heartworm infestation before they can be given this product. Recommended dose should also not be exceeded. Read the dosage and consult your veterinarian before buying this product. Exceeding the dosage can cause tremors, disorientation, dilated pupils, blindness, and loss of appetite and body weight.

It is an easy product to administer. Simply break it down and mix with their regular dog food every 30 days for lasting protection against parasites.


  • Easy to administer
  • Delicious beef flavor
  • Affordable


  • Does not protect against fleas and ticks

Related: The outdoors is fun but have a high risk of contracting parasites. Staying indoors is boring but not anymore thanks to the entertaining and stimulating Kong Classic Dog Toy.

Check the price on Petcarerx

Trifexis Trifexis

Price: Approx. $99.89

Dosage: Once monthly

Age and weight: 8+ weeks of age, weighing 5+ lbs

Features: Beef-flavored tablet contains spinosad and milbemycin oxime

Best use: Prevention of heartworm, adult hookworm, adult roundworm, and adult whipworm infections and fleas

Description: Trifexis is a beef flavored chewable tablet that kills and prevents infestations while protecting against heartworm, adult hookworm, adult roundworm, adult whipworms and fleas. It is a once-a-month medication you can give to your dogs and puppies as young as 8 weeks old and weighing 5 lbs and more.

This medication requires a prescription from your vet as it contains spinosad and milbemycin oxime. The former is an insecticide that is toxic to fleas killing them before they can lay eggs. The later is a broad spectrum antiparasitic effective against heartworms, roundworms, hookworms, and whipworms. Spinosad starts working within 30 minutes and is known to kill 100% of biting fleas within 4 hours. It also kills flea eggs to prevent them from hatching.

Trifexis is a very effective heartworm preventive mediation and flea killer or repellent. It is easy to administer and should be given to dogs with their meals. However, caution should be exercised if your dog suffers from epilepsy. Consult your veterinarian if your dog is experiencing excessive drooling, diarrhea, cough, decreased activity or decreased appetite.


  • Very effective against parasites
  • Easy to administer
  • Attractive beef flavor


  • Very expensive

Related: Mix the product with your dog’s food using the Stainless Steel Dog Bowl from URPOWER. It features a No Spill Non-Skid Silicone Mat for easy clean-ups and more efficient feeding.

Check the price on Petmeds


Heartworm preventive medicine can help save your dog’s life. However, even if your dog is on year-round medication, it is still important to get them tested regularly. Even though heartworm medicine is effective, your dog can still get infected especially if you forgot a dose or neglected to administer it on time.

The best heartworm prevention medicine does not only prevent dogs from heartworms but also protects from common pests like fleas, ticks and intestinal parasites all in one medication.

A dog and a cat playing together

As responsible dog owners it is important to prevent pets not only from heartworms but from all possible parasites that can have a drastic effect on their health. Regular veterinary check-ups can also help identify possible health concerns and keep your dogs healthy and safe from parasites.

What do you think about the products that were reviewed? Do you have experience using any of these products? Were they effective in preventing heartworm? Tell us by leaving your comments below.

About the author
Wyatt Robinson
Wyatt Robinson

Wyatt Robinson had a great 25-years career as a veterinarian in United Kingdom. He used to be a member of British Veterinary Association and worked in 3 pet hospitals in London and Manchester. He is shining when he sees his pets healthy and full of energy and it is his duty to help other dog owners to keep their best friends full of life.