Ask the Vet

Twelve-Month Heartworm Prevention for Dogs

Dogs need to be protected against heartworms year-round, with annual preventions helping to make that easier. (DTN/Progressive Farmer file photo by Jim Patrico)


I have heard there is a once-a-year shot to prevent heartworms in dogs. Does it work? Is it safe?


The Proheart 12 injection is the once-a-year heartworm preventative you're talking about most likely. It was approved and released in 2019. We actually participated in the company's clinical trials for Proheart 12, and we have used it extensively for our clients' dogs since it came on the market. We were impressed with its safety during the trials. While it's new here in the U.S. to many people, this preventative has been approved in Australia since 2001. It is the most commonly used heartworm preventative in that country, and as such, has had an excellent safety profile with millions of doses given.


Editor's Note:

Please contact your veterinarian with questions pertaining to the health of your herd or other animals. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.

Write Dr. Ken McMillan at Ask the Vet, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email