ProHeart 12: Prevents Heartworm for One Year

One injection of ProHeart 12  prevents Heartworm infections for a full 12 months and treats existing hookworm infections, removing the need for monthly heartworm prevention.

ProHeart vs Monthly Prevention

ProHeart wins on Compliance:

I love the monthly preventatives, but it’s hard to remember to give pets their monthly allotment. Compliance is a huge complication when it comes to preventing heartworm disease. Hopefully ProHeart will be a big step in fixing these issues. Just go to your vet for a health check and heartworm test. If your pet is healthy and heartworm free, they can get a ProHeart injection to protect them from heartworm all year long.

Monthly wins in Coverage:

The only drawback I can see to ProHeart is that it only prevents heartworm and cures hookworm infections which is far less than Heartgard  or Revolution in the parasite prevention coverage but heartworm is the biggest long term threat so get that one dealt with first and ask your vet if there is anything additional you need to be concerned with.

Proheart is not for cats. BOOO!!


A good friend of mine was very concerned when I first mentioned this product on My New Pet’s Facebook page. I mean, this drug does have a sordid past.

  • 2004 – Fort Dodge product ProHeart 6 recalled due to health risk, including deaths.
  • Fort Dodge started safety testing and found the solvents used in the injection were allergenic and found new ones. The noted adverse reports from overseas dropped. (never recalled over seas so they continued to use ProHeart 6 during the USA downtime)
  • 2008 – FDA approved relaunch of ProHeart. Rules put in place. Veterinarians and staff had to certify to use the product.
  • Fort Dodge was bought out by Zoetis (Pfizer) and their marketing and development teams got a hold of it. This is when I certified to administer this product as there are a lot more steps than the average injection. For safety reasons, Pfizer required this certification before allowing us to purchase ProHeart 6.
  • 2010 – Sales went up, but not the issues. Safety and efficacy improved. FDA council looks into it.
  • 7-2-19: FDA approved ProHeart 12

Quotes from the FDA Approval:

“Heartworm disease is a serious disease that results in severe lung disease, heart failure, other organ damage, and death in pets, mainly dogs, cats, and ferrets.”

“Adverse events observed in the U.S. field study for ProHeart 12 included vomiting, diarrhea, decreased appetite (anorexia) and seizures and occurred in a similar rate to those dogs that were in the control group. The cases of anorexia observed in the study were generally mild and short in duration, and all cases resolved by the conclusion of the study.”

“In addition, two dogs treated with ProHeart 12 experienced mild to moderate hypersensitivity-related drug reactions within the first 24 hours of the initial treatment. Both dogs experienced full recoveries, and neither dog had a reaction when they received a second dose of ProHeart 12 a year later. Some dogs also experienced injection site inflammation.”

The last one we have had a few cases of in hospital with the ProHeart 6. The dogs had a slight allergic reaction to the first injection but not the second.

Minimizing Risks

The whole point behind prevention is to provide your pet with a long, healthy life, which is why we take precautions, even with preventatives. If it’s a thing (food, treat, medication, supplement) someone, somewhere is going to be allergic to it. We do our best to minimize this. With ProHeart in particular, these are our rules:

  • Exam has to be done to make sure your pet is healthy and happy. We will not administer to sick, debilitated or underweight animals.
  • A negative result on a heartworm test is required. ProHeart, as well as most heartworm prevention, does not kill adult heartworms and can sometimes do more harm than good in a heart congested with worms.
  • Not to be given with vaccines. Risk of anaphylaxis (allergic reactions) increases when given with vaccinations.


Freedom of Information Summary.

Official Indications: For use in dogs 12 months of age and older for the prevention of heartworm disease caused by Dirofilaria immitis for 12 months. For the treatment of existing larval and adult hookworm (Ancylostoma caninum and Uncinaria stenocephala) infections.