It's the time of year when mosquitoes are out ready to make a tasty snack out of your dog or cat. That means that the risk of heartworms for your pet are more prevalent because mosquitoes carry heartworms. I decided to make a list of common heartworm prevention medications to help pet owners be able to tell the difference between all of them. I know it can get confusing when choosing heartworm medicine. There are so many different brands available today and they all do different things.
Please also note that I will only be going into the details about heartworm prevention in this post. Some products do provide protection from fleas and other parasites as well. I hope to do a similar post about flea prevention in the future.
Heartgard Plus
Heartgard Plus for Dogs.
Photo via Jo & Joey
Heartgard Plus is probably the most popular form of heartworm prevention available for dogs. They also make Heartgard for cats. It comes in a soft meaty chew that most dogs love. It's safe for dogs who are older than 6 weeks. It's given once a month - most vets recommend to use heartworm prevention year round, depending on where you live. It contains the drugs Ivermectin and Pyrantel pamoate. Both are common dewormers for many types of animals. My personal experience with Heartgard has always been positive.
The drug Ivermectin kills any of the baby heartworms a dog may have picked up during the month's time since they last took their heartworm medication. I've read some misinformation lately about heartworm prevention and how it works and just want people to know that it's a dewormer... it kills worms that have already begun to live in your pet. The Pyrantel will kill and protect against roundworms and hookworms the same way.
Generic Brands of Heartgard Plus
There are some cheaper generic brands of Heartgard Plus available as well. I actually use one of them for my own dog. It's called Iverhart and has the same ingredients and does the same things as Heartgard. The only real difference is that Iverhart comes as a hard chewable flavored tablet. Many picky dogs do not like this. Fortunately, my Shiner doesn't mind so much. I've always had good results with this heartworm prevention medication.
Tri-Heart Plus is another cheaper generic version of Heartgard Plus. It contains the same ingredients, but again comes as a chewable hard tablet. I have no personal experience with this brand of heartworm medicine.
Sentinel
Sentinel is another oral heartworm preventative. It does not contain Ivermectin, however. This may be a good drug choice for dogs who are allergic to Ivermectin. Sentinel contains the drug Milbemycine oxime which is effective against heartworms. It's a once a month hard chewable flavored tablet. Dogs must be 4 weeks old and over 2 lbs to be able to take Sentinel.
Sentinel also protects dogs against other parasites including roundworms, whipworms, hookworms, and flea eggs. This protection is offered from the drug Lufenuron. Many pet owners get confused and think that Sentinel is a flea prevention. It can help with fleas, but it will not prevent adult fleas from living on your dog. It only sterilizes them and makes them unable to reproduce. I have had a positive experience with Sentinel.
Interceptor is a cheaper generic version of Sentinel that I've also had positive experience with.
Trifexis
Trifexis is a chewable flavored tablet for dogs that is given once a month. It protects dogs from heartworms as well as fleas, hookworms, roundworms, and whipworms. It's safe to give to dogs that are older than 8 weeks and weigh more than 5 lbs. The active ingredients in Trifexis are Milbemycin oxime and Spinosad.
I personally don't have any experience with this heartworm preventative option and haven't heard too much about it.
Revolution for Dogs and Cats
Now we are starting to get into some of the topical heartworm preventatives available to pets. Revolution is a monthly topical heartworm prevention. Revolution offers a product for dogs as well as cats. Be sure to use the appropriate medication for your cat or dog. It's not safe to use dog medicine on cats.
The active ingredient in Revolution for Dogs is Selamectin. It's labeled for use to provide dogs with additional protection against fleas, flea eggs, ear mites, sarcoptic mange, and American dog ticks. It can be given to dogs who are at least 6 weeks old. I personally have not had a good experience with Revolution for heartworms. Many dogs were still coming up heartworm positive while taking Revolution, so our clinic actually stopped selling it. It is great for the treatment of other parasites though.
Revolution for cats also provides monthly heartworm protection in a topical form. In addition to heartworms, it is labeled to protect against ear mites, fleas, flea eggs, one type of hookworm, and one type of roundworm. It also contains the drug Selamectin.
Off label, I have seen this drug used for rabbits and ferrets. We've used it to treat ear mites, sarcoptic mange, maggots and more on a variety of animals. This doesn't mean you should try using Revolution on other pets without the consent of a veterinarian.
Advantage Multi for Dogs and Cats
Advantage Multi is another popular topical heartworm preventative for both dogs and cats. Again, there are separate products available for each species. Advantage Multi for Dogs is also effective against fleas, heartworms, roundworms, and whipworms. Dogs who are older than 7 weeks and weigh more than 3 lbs can take Advantage Multi. It contains the drug Moxidectin, which takes care of the heartworms and Imidacloprid which takes care of the other parasites. I've had good experiences with this drug and would recommend it. Especially if you're looking for something that protects against both heartworms and fleas. Because it is a two in one drug, it is more expensive. However, the cost adds up to be about the same as if you bought heartworm and flea prevention separately.
Cats get heartworms too.
Photo via Misty
Advantage Multi for Cats is effective in the prevention of Feline Heartworm Disease. Yes, cats get heartworms too. If you're interested in learning more about this, I've written an article about it that you can read. Advantage Multi for Cats is a topical once a month prevention that is safe to use on cats that are older than 9 weeks and weigh more than 2 lbs. It's also effective against fleas, roundworms, hookworms, and ear mites. It contains the drugs Moxidectin and Imidacloprid. I've also had good experiences with Advantage Multi for Cats.
Choosing Heartworm Medicine - Which One is Right for Your Pet?
Choosing heartworm medicine can be difficult. I hope this list has helped you clear up the differences between all of the common preventative medications available. They all do very different things and all contain different drugs. I have found that many pet parents can become overwhelmed choosing heartworm medicine for their pets.
If heartworms are a concern where you live, your pet should be taking the proper dose of heartworm medication year round. Mosquito repellents are not adequate forms of heartworm prevention, although they can be helpful.
Also, it is common practice for a veterinarian to perform a heartworm test once a year. A negative result is needed before more heartworm prevention medicine can be prescribed again. Just like with people, dogs and cats need to see their doctors on a regular basis to continue receiving medication. Some people will fuss about this, but just know that it is a very common practice.
Are heartworms a threat where you live? What type of prevention do you use?
Disclosure: I am in no way affiliated with any of the brands mentioned above nor was I compensated for talking about them. I am just sharing my knowledge and experience of the different brands of heartworm prevention medications available on the market.