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20 Best Dog Heartworm Medicine

Written by Jay
BsC (Hons) Animal Behaviour & Welfare graduate with a passion for advocating for misunderstood animals.
Published on
Tuesday 1 September 2020
Last updated on
Tuesday 9 May 2023

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Heartworms appear where mosquitoes live. From a single mosquito bite, your furry friend can experience one of the worst situations it can ever have in its entire life. Fortunately, you can rest a little easier because this article will help you with this problem!

Grab your paper and pen to note the best heartworm medicine for dogs.

20 Best Dog Heartworm Medicines

Before we proceed to the list of selections for heartworm medication, let us first look at this table to provide you with an initial introduction to these brands.

Our Best Pick:

To name our top pick, Heartgard© Plus Chew is an oral medicine that combines efficacy, versatility, and budget-friendliness. Continue reading to know more!

Product NameFlavorBenefitsWeight RangeAge RangeRating
Heartgard© Plus Chew for DogsBeefPerfectly fights against heartworms, hookworms, roundworms, whipworms, and tapeworms and prevents larvae from reproducing  Up to 100 lbs.All ages4.9
Interceptor© Plus Chew for DogsChickenA vet-prescribed medicine for treating and controlling adult heartworms, whipworms, tapeworms, hookworms, and roundworms2 to 100 lbs.Six weeks and older4.8
Simparica© Trio Chewable Tablet for DogsLiverEffectively handles different parasites, including heartworms, hookworms, roundworms, fleas, ticks, and larvae 2.8 to 132 lbs.Eight weeks and older4.8
Tri-Heart© Plus Chewable TabletsBeefRepels and prevents heartworms while killing and treating hookworms and roundwormsUp to 100 lbs.Six weeks and older4.7
Sentinel Spectrum Chew for DogsBeef and BaconHelps deal with adult fleas, hookworms, tapeworms, whipworms, and roundworms aside from heartworm prevention  2 to 100 lbs.Six weeks and older4.7
Best Dog Heartworm Medicine

Heartgard© Plus Chew for Dogs

If you wonder what heartworm medication is best for dogs, Heartgard© tops the chart for its health benefits and reasonable price. It is a beef-flavored oral medicine that can fight against heartworms, hookworms, roundworms, whipworms, and tapeworms. Moreover, it can be perfect for dogs of all ages and weights!

1. Heartgard Plus Chew for Dogs, 51-100 lbs

Once your dog gets tested for heartworm infection, you can administer this preventive oral medicine to deal with such illnesses. Since its active ingredients include ivermectin and pyrantel, it can also treat and control hookworms, roundworms, tapeworms, and whipworms. Furthermore, it can also eliminate those parasitic larvae, preventing them from turning into adults and reproducing eggs.

If you have problems making your dog eat its medicine, you can worry less because Heartgard has a natural beef flavor that attracts canines to wobble it up. Your pregnant dog can also be happy with this pill!

Nevertheless, it is best to prepare for possible side effects upon administering this medication to your four-legged friend. It can suffer from vomiting, diarrhea, lethargy, drooling, and other consequences. You can check the product’s safety label to learn more about this.


  • Dogs love the taste of natural beef
  • Eliminates four types of parasitic worms aside from heartworms
  • Easy to administer
  • Recommended by veterinarians
  • Suitable for all age ranges, including pregnant dogs


  • Your dog can suffer from a wide range of side effects
  • A negative heartworm test from your veterinarian is necessary before administering this medicine
  • You will need to give it monthly, all year long to be effective 

2. Heartgard Plus Chew for Dogs, 26-50 lbs

Treating your dog’s heartworm sounds better if it is beef-flavored, right? So, you better not let the opportunity pass without trying this tasty, chewable medicine for dogs! You can treat and control your furry friend’s heartworms, roundworms, tapeworms, hookworms, and whipworms. Moreover, it can also restrain larvae from turning into adults by eliminating them in no time.

Aside from that, this medicine is perfect for dogs of all ages, involving pregnant canines. Nonetheless, you might need to be alert and prepared to call your veterinarian if such side effects occur. These effects may include vomiting and diarrhea within 24 hours of administration, lethargy, hypersalivation salivation, and staggering. Fear not because the product’s safety label will show more about these.


  • With a reasonable price worthy of its benefits
  • Suitable for dogs suffering from seizures
  • Works perfectly against heartworms, tapeworms, roundworms, whipworms, and hookworms
  • Natural beef flavor
  • Easy to administer


  • You can notice common to rare side effects after administering the oral medicine
  • You will need to have a negative heartworm test signed by your veterinarian before you can administer it
  • Requires a year-round monthly administration to be effective

3. Heartgard Plus Chew for Dogs, up to 25 lbs

If you want Heartgard Plus Chew but your dog is not big enough to be compatible with the previous doses, you can opt for this one, which is perfect for canines up to 25 lbs. It can eliminate and prevent heartworms, tapeworms, hookworms, roundworms, and whipworms. Aside from that, it can also get rid of those larvae and prevent them from developing and reproducing. You can also use this pill with flea collars, shampoos, dips, vaccines, and antibiotics for better results.

In addition, this heartworm prevention for dogs has a natural beef flavor that attracts canines to eat them willingly. However, we cannot avoid that some medications will bring side effects, so it is best to prepare for them instead. You may notice diarrhea, vomiting, hypersalivation, and other consequences. You can refer to the product’s safety label for more information.


  • Effectively prevents and controls heartworms, tapeworms, roundworms, whipworms, and hookworms
  • No problem in administering it to dogs due to its natural beef flavor
  • Reasonable price
  • Suitable for dogs with sensitive stomachs, seizures, and pregnant canines
  • Soft medicine perfect for dogs with missing teeth


  • It can lead to different side effects
  • Your dog must obtain a negative heartworm test from its veterinarian before you can give this medication
  • A monthly administration for an entire year is necessary to ensure the effectiveness

Interceptor© Plus Chew for Dogs 

Satisfy your dog’s love for chicken while combating heartworms and parasites with Interceptor© Plus Chew! This chicken-flavored dog heartworm medicine is a worthy alternative to Heartgard©. Furthermore, it is a chewable monthly preventative for hookworms, tapeworms, roundworms, and whipworms. Not to mention that most veterinarians also prescribe this pill to pet parents!

1. Interceptor Plus Chew for Dogs, 2-8 lbs

Do you often forget when to give your four-legged friend heartworm medication? This product will help you solve that because every purchase will come with stick-on labels for your monthly reminder in the calendar!

In terms of efficacy, this vet-prescribed pill can control adult heartworms, whipworms, tapeworms, hookworms, and roundworms. Furthermore, it is chicken-flavored and chewable, so you can be confident that your dog will eat it without difficulty.

Nonetheless, this medicine can also bring side effects like most brands. That includes vomiting, diarrhea, lethargy, weakness, salivation, and convulsions. Still and all, these consequences will not be regular because you only need to administer this pill once a month. You can give it to your dog by hand or break it into smaller pieces to add to your furry friend’s favorite dog treat. 


  • Dogs can tolerate the medicine well
  • It attracts dogs to chew it up due to its tasty chicken flavor
  • With an appealing scent that smells like a dog treat
  • Works effectively against five types of parasites
  • With a reasonable price


  • The medicine can dry up and become hard to chew for dogs
  • It can bring different side effects
  • Requires a prescription from a veterinarian

2. Interceptor Plus Chew for Dogs, 8.1-25 lbs

Since we already have beef-flavored medicine earlier, it is about time for some chicken-flavored ones! Interceptor Plus Chew is a tasty yet chewable medication against heartworms. You can administer it quickly and conveniently, for you can choose whether to give it by hand or break it into smaller pieces to mix with dog foods. Yet, you only need to remember that your dog must chew it and not swallow it as a whole.

Aside from the tastiness and ease of administration, you can never forget this product’s efficacy. Its ability to treat and control parasitic worms is effective and quick, and even professional veterinarians recommend this heartworm medicine to most pet owners.

However, your dog can still encounter different side effects from this pill, including diarrhea, vomiting, lethargy, salivation, weakness, and convulsions. It is only somewhat good that you only need to give it once a month, and the stick-on labels can remind you when! 


  • Perfect for fighting against five types of parasites and worms
  • Easy to administer and safe to eat
  • Highly recommended by veterinarians 
  • With an attractive chicken flavor that entices dogs to wobble it up
  • With stick-on labels for monthly reminders


  • It can become hard and challenging to break into smaller pieces
  • It can lead to side effects
  • You will need a prescription before you can purchase it

3. Interceptor Plus Chew for Dogs, 25.1-50 lbs

Taking medicines can be stressful for dogs who hate them, but this heartworm medicine can make things easier for you and your pup because it only requires administration once a month! If such instances happen that you forget when was the last time you gave this to your dog, you can use the stick-on labels to mark your calendar. That will also help you monitor its health regularly as the product effectively eliminates heartworms, hookworms, tapeworms, whipworms, and roundworms.

In addition, this chicken-flavored medication is a broad-spectrum parasiticide that is also easy to administer. Its chewable texture allows you to give it by hand or add it to any dog treat or food. Nonetheless, you may want to prepare for possible side effects of taking this medicine. Its side effects involve diarrhea, lethargy, seizures, weakness, vomiting, and drooling.


  • Effectively works against heartworms, roundworms, hookworms, whipworms, and tapeworms
  • Cheaper than other brands, such as the Sentinel
  • With an appealing chicken flavor that attracts dogs
  • Easy to administer
  • Requires once a month only, which is less stressful for canines who dislike medicines 


  • The medicine can be rock solid, thus challenging to chew 
  • Your furry friend can encounter side effects after eating it
  • A prescription is necessary before purchasing it

4. Interceptor Plus Chew for Dogs, 50.1-100 lbs

Your pup can get heavy up to 100 lbs., but never the burden of its heartworm disease because Interceptor Plus Chew can make it lighter! This vet-recommended oral medicine can kill and prevent adult heartworms, whipworms, tapeworms, hookworms, and roundworms. Moreover, its natural chicken flavor makes it attractive for dogs to take the pill willingly. Since it is also chewable, they will not have difficulty eating it. 

Still and all, we advise noting your veterinarian’s contact number and preparing for aid kits because your dog can suffer from side effects. It can experience lethargy, vomiting, diarrhea, drooling, and weakness, and these effects will appear once a month whenever you administer the medicine to your pup. You can know that by using the stick-on labels from the package to mark your calendar.


  • The package has stick-on labels for monthly reminders
  • It can effectively fight against heartworms, roundworms, hookworms, whipworms, and tapeworms
  • Reasonable price
  • With a tasty chicken flavor and smells like dog treats
  • Tolerable for dogs


  • It can be challenging for your dog to chew or for you to break it into pieces
  • It can have side effects
  • You must have a prescription to buy this medicine

Simparica© Trio Chewable Tablet for Dogs

If you need something with versatility, Simparica© will not come last because its active ingredients can do wonders! You can administer it to handle different parasites, including heartworms, hookworms, roundworms, fleas, ticks, and larvae. Moreover, its flavor will never do you wrong because it is tasty enough to attract canines to eat it up!

1. Simparica Trio Chewable Tablet for Dogs, 2.8-5.5 lbs

This heartworm prevention for dogs may not be our first pick, but it is the first and only medicine that has combined sarolaner, moxidectin, and pyrantel. Consequently, these active ingredients enabled this product to prevent heartworm disease and flea infestation, kill ticks, and treat or control roundworms and hookworms.

It also helps eliminate larvae to prevent them from being adult parasites. On the other hand, it also has a liver flavor, thus making it palatable and easy to administer.

In terms of side effects, this medicine will bring less, including only vomiting and diarrhea. Some users report that these consequences are also rare or unlikely to happen usually.

A significant pitfall of this product is that even though it can prevent flea infestation, most pet owners argue it is not effective enough to kill fleas. You may want to choose another brand to fill in this gap.


  • It has lesser side effects than other brands
  • Works fast and effectively 
  • Prevents, kills, and controls parasites
  • With a liver flavor that your furry friends like
  • Recommended by veterinarians


  • It might be ineffective against fleas
  • Suitable for dogs only
  • Not effective for breeding, pregnant, and lactating dogs

2. Simparica Trio Chewable Tablet for Dogs, 5.6-11.0 lbs

If you have a pup eight weeks or older suffering from heartworm disease, this product can be the best dog heartworm medicine to help you! Thanks to its sarolaner, pyrantel, and moxidectin ingredients, you can cure and control hookworms and roundworms, prevent heartworms and fleas, and annihilate ticks. Also, its liver-flavored chewable texture makes the pill become enticing enough to attract canines.

Despite its fewer side effects, which only include vomiting and diarrhea, you may notice that this product is slightly ineffective in killing fleas. It can only prevent and control them, but not eliminate them. Other than that, there’s nothing much to worry about!


  • Works perfectly in fighting against heartworms and other parasitic worms
  • Liver-flavored to entice dogs to eat this medicine willingly
  • Fewer side effects (vomiting and diarrhea only)
  • No problem in administering due to its smell and tolerability
  • Vet-recommended for an all-around treatment


  • It can be ineffective in killing and eliminating fleas
  • Not suitable for pregnant, lactating, and breeding canines
  • Does not repel mosquitoes

3. Simparica Trio Chewable Tablet for Dogs, 11.1-22.0 lbs

Does your four-legged friend love eating livers? If that is the case, you better grab this chewable tablet to satisfy its cravings while aiding its heartworm disease! It can also eliminate ticks, prevent fleas, thwart larvae from being adult parasites, and treat round and hookworms. Also, it is suitable for canines eight weeks or older.

Aside from that, Simparica Trio only brings two side effects, including diarrhea and vomiting. Yet, pet owners emphasize that it is rare for their furry friends to suffer from these side effects, which is beneficial for many. The only problem is that this medicine may not be enough to kill fleas because it can only avert and control them but not destroy them.


  • Easy to break into smaller pieces
  • Dogs willingly eat the medicine, with or without additional food or treat
  • Effectively works against heartworms, hookworms, and roundworms 
  • Eliminates larvae to prevent them from developing
  • Requires once a month of administration only 


  • It does not kill fleas
  • Suitable only for dogs
  • This does not apply to lactating, pregnant, and breeding dogs

4. Simparica Trio Chewable Tablet for Dogs, 22.1-44.0 lbs

Whenever you feel hopeless about whether or not you can cure your pup’s heartworm disease, do not forget that Simparica Trio exists to help you! This oral medicine can kill ticks, remove hookworms and roundworms, and prevent heartworms and fleas from spreading inside your dog’s body. Also, this liver-flavored medication is perfect for your furry friends eight weeks old or more.

One significant advantage of this product is that it only leads to two side effects, vomiting and diarrhea, unlike other brands that bring a lot. Nevertheless, one substantial pitfall is that it cannot kill fleas because the manufacturers intended it for prevention only and not elimination. Still and all, that is somewhat acceptable because this pill focuses on heartworms! 


  • Suitable for dogs eight weeks old and older
  • Fewer side effects than previous brands
  • It kills parasites and prevents them from laying eggs
  • Eliminates larvae to thwart them from developing
  • It attracts dogs to eat this medicine due to its tasty liver flavor


  • User reviews reported that it is ineffective in eliminating fleas
  • Not suitable for repelling mosquitoes
  • You cannot give this to lactating, breeding, and pregnant dogs

5. Simparica Trio Chewable Tablet for Dogs, 44.1-88 lbs

Who’s in for a liver-flavored medicine that brings fewer side effects than other brands? Don’t waste the chance to have this Simparica Trio that can prevent heartworm and flea infestations, kill different ticks, and control hookworms and roundworms! It can also extinguish parasitic larvae that can mature and reproduce. Moreover, this product is perfect for dogs eight weeks or older, weighing 44.1 to 88 lbs. 

In terms of administration, you can give this vet-recommended medicine alone by hand or mix it with your dog’s favorite peanut butter or dog treat. However, if you want something that can work better for eliminating fleas, you can opt for another brand because Simparica Trio is only for preventing flea infestations


  • Suitable for preventing, killing, or controlling heartworms, hookworms, and roundworms 
  • Comes in a desirable liver flavor your furry friend will surely love
  • You can either mix it with a treat or administer it as it is
  • Lesser side effects


  • You may notice that it will not work effectively in fleas
  • For dogs only
  • Pregnant, lactating, and breeding dogs will not benefit from this medicine

6. Simparica Trio Chewable Tablet for Dogs, 88.1-132.0 lbs

This product can be one of the fewest heartworm medications that can cater to dogs weighing up to 132 lbs. It can work effectively to combat and prevent heartworms, hookworms, and roundworms while adding extra protection to fleas and ticks. Consequently, veterinarians also recommend this versatile medicine significantly because it only brings two side effects, including vomiting and diarrhea.

Simparica Trio also possesses a palatable liver flavor that can make the administration hassle-free and more exciting for your furry friend. Still and all, you can only give this pill to dogs eight weeks or older. It can also be ineffective for removing fleas because its manufacturers intended to prevent flea infestations but not destroy them.


  • Effectively treat and prevent heartworms, hookworms, and roundworms
  • It can contribute to flea and tick control
  • With a liver flavor that allows the administration of medicine to become easier
  • Recommended by veterinarians for an all-around medicine
  • Fewer side effects


  • It can control fleas but may ineffectively eliminate them
  • Suitable for dogs only
  • Giving this to pregnant, breeding, and lactating dogs is not advisable

Tri-Heart© Plus Chewable Tablets

Being on a budget will not stop you from giving the best heartworm prevention to your dog because Tri-Heart© Plus Chewable Tablets can help you save money! This budget-friendly medicine can safeguard canines from heartworm infestations, especially when administered on time. Besides, its delicious taste will not give you trouble giving it to your furry friend.

1. Tri-Heart Plus Chewable Tablet for Dogs, up to 25 lbs

As stated earlier, you have to worry less about how much this medicine will cost you because it is the cheapest option among all brands. It can repel and prevent heartworms while killing and treating hookworms and roundworms. Additionally, this beef-flavored chewable tablet is safe and reported to have caused minimal to no side effects. The rarest instances are upset stomachs, drooling, convulsion, and incoordination.

Yet, despite its endless beneficial characteristics, some pet owners report that their dogs do not like this medicine. Even though it is palatable like a tasty dog treat, their pups do not eat it. Also, the pill can be hard to chew, which justifies one reason why canines ignore it.


  • The cheapest option among all brands 
  • It brings no side effects to dogs
  • Effectively prevents heartworms and diseases associated with this parasite 
  • Quickly kills roundworms and hookworms
  • Recommended by veterinarians


  • Some dogs might dislike the medicine
  • It can be hard to chew or rock solid to break into pieces
  • It does not repel ticks, mosquitoes, and fleas

2. Tri-Heart Plus Chewable Tablet for Dogs, 26-50 lbs

Paws down to the safest dog heartworm medicine that brings the fewest to no side effects! Rarest reports only say it can lead to upset stomachs, convulsions, incoordination, and drooling, but these are entirely uncommon. Aside from that, it is also the most budget-friendly option for those financially struggling to treat parasitic worms.

In terms of efficacy, this chewable medicine can repel or prevent heartworms and associated diseases. It can also assist in treating and eliminating hookworms and roundworms inside your dog’s body. Notably, its beef-flavored tablet is palatable enough to attract canines to eat it up. The only problem is that, although it is tasty, a few pet owners report that their furry friends still refuse to take it. 


  • Suitable for dogs that are six weeks old and older
  • Your dog will not suffer any side effects from this medicine 
  • The cheapest option for those with low budgets
  • It repels and prevents heartworms while killing hookworms and roundworms
  • It can smell and look like a dog treat


  • Challenging to chew
  • Some dogs will refuse to eat it
  • Ineffective for repelling ticks, fleas, and mosquitoes

3. Tri-Heart Plus Chewable Tablet for Dogs, 51-100 lbs

You read that right! The Tri-Heart© Plus Chewable Tablet also has a version for dogs up to 100 lbs. Even though your dog gets heavier, you can still feel the lightness in your pockets because this product remains cheap and affordable to purchase.

Still, it does not compromise its effectiveness in removing and controlling hookworms and roundworms. It also works perfectly in preventing and repelling heartworms.

If you are worried about the side effects, you can breathe easier because this product does not bring one. You can only encounter upset stomachs, convulsions, drooling, or incoordination, but these come in rare instances. Although this medicine also ranks high due to its natural beef flavor and palatability, some dogs may dislike and refuse to ingest it.


  • The most affordable option if you do not have the budget to purchase expensive medicines
  • No side effects
  • Recommended by veterinarians for preventing heartworms and eliminating hookworms and roundworms
  • Easy to administer due to its delicious taste


  • A few dogs can dislike the medicine
  • Your dog can have trouble chewing it
  • Not suitable for repelling fleas, ticks, and mosquitoes

Sentinel Spectrum Chew for Dogs

Do you want something that goes beyond what you need? This heartworm medicine for dogs will also help you deal with adult hookworms, tapeworms, whipworms, and roundworms aside from heartworms. Also, your problem with fleas can get solved with Sentinel Spectrum Chew! No worries about its administration because it is also chewable for canines.

1. Sentinel Spectrum Chew for Dogs, 2-8 lbs

You no longer need to look further if you want something tasty, for this oral preventive medicine is beef and bacon-flavored! It is a flavorful tablet that can prevent heartworms, adult hookworms, whipworms, and roundworms. Furthermore, it also safeguards your pup from the development of flea eggs. 

However, a primary downfall of choosing this is that it can dry up and become rock solid, thus making it challenging for your dog to chew it or for you to break it into pieces. It can also fall short when eliminating heartworms because it can only repel them and not kill them. This may not be the best option for you to cure your furry friend’s heartworm disease.


  • Prevents fleas and heartworms
  • Kills roundworms, hookworms, and tapeworms
  • Beef and bacon-flavored medicine that entices dogs to eat it willingly
  • Reasonable price
  • You can choose whether or not to mix it with a treat


  • It can be slightly hard to chew
  • The medicine does not kill heartworms but only repels and prevents them
  • It can have side effects

2. Sentinel Spectrum Chew for Dogs, 8.1-25 lbs

A beef and bacon-flavored chewable sounds delicious today, so why not give it while repelling heartworms, adult whipworms, roundworms, and hookworms? Not to mention that it can also prevent flea eggs from hatching and developing into mature ones. Also, its tastiness can match perfectly with other dog treats and meals, making your dog more excited to take this pill.

Nonetheless, this medicine can become dry in the long run, causing it to turn solid and hard to chew. You can also face difficulty breaking it into smaller pieces. Additionally, it can become ineffective in removing heartworms from your dog’s body once diagnosed with a heartworm infection. That is because this pill can only repel heartworms. 


  • An affordable option
  • It can deal with fleas, heartworms, and other parasitic worms
  • You can mix it with peanut butter and other treats, but it also works perfectly without any additional food
  • With beef and bacon flavors


  • It only repels and prevents heartworms, not eliminates them
  • It can be hard to chew
  • Your dog can experience side effects

3. Sentinel Spectrum Chew for Dogs, 25.1-50 lbs

Sentinel Spectrum does not come the very last when we speak of monthly oral preventive medicines. Like other brands, it soars high in controlling heartworms, adult hookworms, roundworms, and whipworms. It also safeguards your dog from possible flea infestations and prevents flea eggs from developing. Not to brag that its beef-flavored pill is palatable too!

Yet, you can face a significant pitfall in choosing this product due to its several gaps. First, the medicine can dry up and become challenging for your dog to eat. Also, it may not be the best option for removing heartworms because it can fail to eliminate them, given that it is only for heartworm prevention. If you want something that can aid your dog’s heartworm disease, we advise looking for another brand.


  • Attract dogs due to its tasty beef and bacon flavor
  • The price is reasonable for an all-around medicine
  • Easy to administer and safe to eat
  • Suitable for your furry friends that are six weeks old and older


  • It does not eliminate fleas and heartworms but rather repels and prevents them
  • Hard to chew
  • With side effects

4. Sentinel Spectrum Chew for Dogs, 50.1-100 lbs

Here is Sentinel Spectrum for dogs weighing 50.1 to 100 lbs. to conclude our list of dog heartworm preventive medicines. This natural beef-flavored chewable medication can protect your furry friend from possible heartworm infections and infestations of other parasitic worms, such as hookworms, roundworms, and whipworms. Aside from that, it can also prevent flea eggs from maturing and reproducing.

Despite its benefits in combating heartworms, this product may still be the least option you can choose to make this parasitic worm disappear effectively. Since it only applies to heartworm prevention, you can expect that it can be slightly ineffective in permanently removing parasites. Moreover, it can also get dried up and become hard to chew.


  • No problem administering it to your dog 
  • Dogs like them because they taste like beef and bacon-flavored dog treats
  • A cheap option compared to its benefits
  • Effective against parasites and worms
  • Safe for dogs to take once a month


  • Your dog can suffer from side effects
  • It can be challenging for your dog to chew it
  • It only prevents and repels fleas and heartworms

What Are Heartworm Medicines?

Heartworm disease is a potentially fatal issue for pets worldwide. Large worms that live inside the heart, lungs, and blood vessels of dogs cause this. This causes severe lung disease and heart failure as well as damage to other internal organs. Unfortunately, our furry friends are natural hosts of heartworms. If untreated, heartworm numbers increase up to several hundred.

There are two types of heartworm medicine for dogs: those that treat heartworm infections, and those that prevent heartworm infections. Preventative medicines come as chewable tablets, topical liquids, pills, and injectable medications. The American Heartworm Society recommends that owners should give their pets year-round dog heartworm medicine.

heartworm tablets for dogs
There are different kinds of heartworn tablets for dogs.

Why Do Dogs Need Heartworm Medications?

Noack et al.‘s study on the overview of heartworm disease explains that heartworms are significant parasitic threats to animals worldwide. Unfortunately, according to Vieira et al.‘s research on the prevalence of canine heartworm disease, 83 out of 304 dogs in Portugal get infected with heartworms. Thus, it further signifies that numerous dogs can suffer from heartworm-induced diseases.

If you ask about this parasite’s effect on a dog’s body, it can harm a canine’s vital organs, leading to mortality when not treated on time. It can grow up to 12 inches long and live inside a pup’s heart, associated blood vessels, and lungs. Moreover, it can also lay eggs, reproduce, and grow again, repeating the same process.

Considering that fact, giving the best dog heartworm treatment is the most advisable way to combat such a deadly disease. It can also allow you to prevent time-consuming yet expensive doctor appointments once your dog gets infected with the parasite. Nevertheless, it will be worth noting that your dog must receive the prescribed doses on dates recommended by the veterinarian.

Based on the American Heartworm Society‘s article about heartworm infection in dogs, a dog can get infected with heartworms due to delayed or skipped administration of a preventative dose. Even though you only failed to administer once, your pup’s health can be at stake, especially if you live in a highly-endemic area. Thus, we suggest marking your calendars or setting reminders to keep yourself notified when to give your dog its heartworm medication.

Types of Heartworm Medicine

From pills to capsules, topical to chewable, there is no shortage of options when it comes to taking medication. Surprisingly, there are many differences between the different options that go beyond taste and shelf life. It never hurts to talk to your vet about your options! If your dog refuses tablets and can’t take topical medicines, they should be able to offer alternatives for your pet.


Tablets are relatively cheaper to manufacture. This makes them more affordable. In addition, tablets are more stable and typically have a much longer shelf life than other options. Compared to topical treatments, tablets come in variable forms, including quick-release, delayed-release, and extended-release. After taking tablets, dogs are free to swim and bathe as normal.

As with the other treatment options, tablets come with cons too. They are more likely to irritate the intestinal tract, can disintegrate unevenly, and are often less palatable than chewable tablets. Some dogs refuse to take tablets. Defensive and aggressive dogs may not be able to take tablets without sedation.


Topical treatments are easier to apply in dogs who refuse tablets. Unlike chewable tablets, the ingredients of a topical treatment do not need to be in the bloodstream to start killing parasites. With regular monthly use, some topical treatments reach a steady state. This provides continuous protection from parasites between doses.

On the other hand, topical treatments are more prone to human error. The owner must apply the treatment directly on their pet’s skin, not on the fur, and failing to do so means that the owner could mistakenly believe their pet is protected. In addition, the active ingredients and carriers of the medication often have a bad taste. If your dog licks the product when it is still wet on their fur, it can cause salivation, vomiting, and nausea. Furthermore, some topical medicines require your dog to avoid swimming and bathing after use.


The most obvious advantage of chewable tablets is that they are much easier to consume. If your dog has a hard time swallowing standard tablets, or just doesn’t like the taste, chewable tablets are ideal. If they taste good too, your dog is more likely to want to take them instead of viewing them as a negative experience.

In chewable tablets, they often try to hide bad-tasting ingredients with flavorings and sugar. In addition to this, you should take care to ensure that your dog actually chews the tablets. If your dog is likely to swallow the tablet whole, it’s best to break them up into pieces.

when in doubt consult a vet
When unsure, always check with your pup’s vet.

Possible Side Effects of Heartworm Medicines

We cannot deny that even the best dog heartworm prevention can lead to adverse reactions. For instance, the most prevalent side effect is an allergic reaction, which may involve hives, itching, and a swollen face. Your dog can also have seizures, skin congestion, weakness, urticaria, or low energy levels (lethargy).

Also, it will not be rare to see your furry friend suffer from an upset stomach, leading to vomiting or diarrhea. In several cases, they can also lose their appetite. Hence, your pup can ignore food or refuse to eat, causing a slight weight change.

In addition, other possible side effects your dog may experience after administering heartworm medicines include the following consequences.

  • Pruritus
  • Convulsions
  • Depression
  • Ataxia
  • Anorexia
  • Polypnea
  • Drooling or salivation
  • Hyperactivity
  • Trembling
  • Incoordination

These adverse reactions will likely appear within 24 hours after ingesting the medicine. Nevertheless, we highly advise calling your trusted veterinarian immediately if something severe occurs. If they see that the side effects are becoming alarming, they can recommend changing the medicine brand or the way of administration.

How to Prevent Heartworms in Dogs

As people say, prevention is better than cure, always and in all ways. Luckily, if you do not know where to begin the best heartworm prevention for dogs, you can read these three ways we have listed below to get you started.

1. Regular Check-ups

Routine veterinary visits every six months can contribute to heartworm prevention. They will allow you to monitor your pup’s health and see whether or not immature and mature larvae are present inside its organ systems.

In this case, your veterinarian will help you perform microfilariae concentration tests or antigen tests to check heartworms. Consequently, once your dog gets diagnosed with heartworm disease, you can treat it immediately before it reproduces and becomes more mature.

2. Heartworm Prevention Medicines

One way to the best dog heartworm treatment or prevention is through administering preventative medicines. It helps your dog acquire the necessary nutrients and content to build a solid wall against heartworm infections.

Moreover, many brands like the ones enumerated above also assist in eliminating other parasitic worms, making your pup healthier. You will only need to keep an eye out for possible side effects.

3. Mosquito Repellents

The last thing you can do to prevent heartworm disease is to have mosquito repellents. Since dogs get infected with heartworms through mosquito bites, which are the transmitting agents of microfilaria, repellents can thwart these parasites by producing odors around your pup’s skin. The smell will keep mosquitoes from getting near your dog or discourage them from biting it. 

Dog Heartworm Medicines: FAQs

After knowing the recommended brands and essential information about heartworm medication for dogs, you might have additional questions in your mind right now. Considering that, you can read these frequently asked inquiries below to address everything you want to know further.

What can I give my dog naturally to prevent heartworms?

Aside from administering heartworm medicines to dogs, one way to naturally prevent the threat of heartworm infection is through enforcing a healthy diet. It is best to give foods rich in antioxidants and omega-3 fatty acids to boost your pup’s overall health. Also, you can let your dog take cedar oils, citrus oils, and diatomaceous earth to limit its exposure to mosquitoes.

What is the best heartworm medication for dogs?

Heartgard Plus Chew for dogs has been the top choice for heartworm preventive medicines. A study by Gates and Nolan also reveals that 54% of 2,679 canines use this product to prevent parasitic worms.
It works perfectly against heartworms, hookworms, whipworms, tapeworms, and roundworms. Furthermore, it can remove larvae to avert them from maturing and reproducing.

What is better than Heartgard?

Due to its excellence and effectiveness, Heartgard Plus Chew is the overall top-ranking heartworm medication for dogs. Nevertheless, in terms of the price and side effects, the Tri-Heart© Plus Chewable Tablets are cheaper and have fewer adverse reactions. Other than that, the Simparica Trio can be better when we speak of additional flea and tick control.

What is the safest heartworm medicine for small dogs?

The Tri-Heart© Plus Chewable Tablets is one of the safest brands you can give your small dog to fight against heartworms and other parasites. Unlike other products, this vet-recommended medicine does not produce side effects on canines. Only a few pet owners report the rarest cases of upset stomachs, drooling, and incoordination.

Which is safer, Heartgard or Interceptor?

Comparatively, both products have received approval from the Food and Drug Administration, which means they are certified safe. These vet-prescribed medicines also share similar effectiveness in eliminating heartworms and other parasites, and they also bring identical side effects to canines. However, we recommend choosing Interceptor© for better safety and Heartgard for age appropriateness.

What is the safest flea tick and heartworm medication for dogs?

Simparica Trio is the safest yet leading flea, tick, and heartworm medication for dogs. It can effectively prevent heartworm disease and flea infestation while killing different types of ticks. Moreover, it can aid and control hookworms and roundworms. It also doesn’t bring severe side effects except for vomiting and diarrhea. 

What do holistic vets recommend for heartworm prevention?

Holistic vets advise seasonal or regular oral medicine administration to prevent the risks of heartworm-induced diseases. In this case, the most-recommended product is the Heartgard Plus Chew for Dogs. Since this medication contains ivermectin and pyrantel with no additional dewormers, it is effective against parasites and safe for dogs to ingest.

prevent heartworm disease
Heartworm disease in dogs can be prevented!

Indeed, it is no good to suffer from a disease caused by heartworms and other parasites. As a pet owner, you may also feel worried and saddened to see your furry friend get hurt by this condition.

The best thing to do is to perform safe heartworm prevention for dogs. Luckily, this article has provided everything you must know to handle this situation!

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