ProHeart 12 Gives Dogs a Year of Heartworm Protection

Laci Schaible, DVM, MSL, CVJ
By Laci Schaible, DVM, MSL, CVJ on Sep. 20, 2019

Heartworm disease is a very serious and real concern for pet parents. With canine heartworm infections being reported in all 50 states in the US, heartworm prevention is essential.

However, despite the widespread availability of heartworm preventatives, the rate of dogs infected with heartworm disease has increased, and the use of heartworm preventatives has declined.

Simply forgetting to give your dog these monthly preventatives is the primary factor that contributes to the increase in heartworm cases, according to the American Animal Hospital Association (AAHA).

The solution has come in the form of heartworm prevention shots that protect your dog for six months or a full year—ProHeart 6 and ProHeart 12. While the ProHeart 6 (six-month) heartworm prevention injection has been approved and available since 2008, the ProHeart 12 (yearly) injection was only recently approved by the US Food & Drug Administration (FDA) on July 2, 2019.

Here’s everything you need to know about this new shot that protects dogs from heartworm for a full year.

What Is ProHeart 12?

The ProHeart 12 injection works similarly to ProHeart 6, but instead of providing heartworm protection for six months, it will last a whole year.

It works by slowly releasing microspheres of the antiparasitic drug, moxidectin, over the course of 12 months.

ProHeart 12 is currently the only FDA-approved heartworm prevention product that prevents heartworm disease for a full year. It can also treat hookworms at the time of injection.

Is ProHeart 12 Safe?

Before ProHeart 12 was approved by the FDA, investigators evaluated its safety in laboratory studies and field studies using client-owned dogs.

ProHeart 6 did undergo a voluntary recall in 2004; the studies from the FDA suggest that the issue was the result of some residual solvents used in manufacturing that were allergenic, which caused adverse events in dogs. In response, the manufacturer adjusted how the drug was made.

Since then, there have been extensive safety and efficacy studies, and it was approved and rereleased. According to the current manufacturer, Zoetis, since the reintroduction, adverse reactions are rare and usually not serious.

From the clinical trials, the only reported side effects of ProHeart 12 include vomiting, lethargy, diarrhea, anorexia and hypersensitivity reactions.

It is also worth noting that ProHeart injections have been registered and available in Canada, the European Union (France, Greece, Italy, Portugal, Spain), Korea and Japan, and there have been no recalls or concerns over their safety.

Additionally, ProHeart 12 has been approved and in use in Australia since 2000.

Which Dogs Are Eligible for ProHeart 12?

ProHeart 12 can be used in healthy dogs that are one year or older. Because puppies grow rapidly, they tend to need different dosages of heartworm preventative each month, based upon their weight.

Many vets recommend using oral or topical heartworm meds through year one, then deciding whether to make the switch.

ProHeart 12 has also been found to be safe for dogs that are sensitive to ivermectin, which is a common ingredient in oral heartworm preventatives. 

Talk with your veterinarian to see if your dog is a good candidate.

Should I Use a New Product on My Dog? Does That Make My Dog a “Guinea Pig?”

It is understandable and often wise to not embrace a new veterinary pharmaceutical product before extensive data is available. Despite this, many vets are comfortable with quickly switching to ProHeart 12.

Why the quick adoption? While ProHeart 12 is new to hit the market in the USA, it has been marketed and used—heavily—in Australia for 19 years. This hardly qualifies it as a new product.

While studies have been performed in the US, 19 years of being prescribed more frequently than any other heartworm preventative in Australia, the second largest canine heartworm market in the world, is better than any number of studies any drug company could ever perform, in my opinion.

By: Laci Schaible, DVM, CVJ

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Laci Schaible, DVM, MSL, CVJ


Laci Schaible, DVM, MSL, CVJ


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