Is it necessary that I give my dog heartworm medication?

Hi Mervyn,

Thanks for your question.

There is no vaccination for heartworm. I believe you might be asking about a particular product, which my license prevents me from mentioning the name that you give as an injection and it gives your dog 6 months of protection from heartworm.

Your question is short and simple, but the answer is not simple at all. It depends on many different factors and what you feel is important. I can’t answer the question for you, but I can give you information that will help you make your own decision.

In order to decide whether you should protect your dog against a disease, you first need to consider the risk of getting that disease. The chance of your dog contracting heartworm will vastly differ based on where you live. You should ask your veterinarian about the potential risk in your area. Here, in Toronto Canada, the risk would be about 1 in a 1000 to 1 in 10,000. Although the risk may be low, the impact if it did occur is very serious and could impact your pet’s health permanently. Many people use preventives because they are very effective and completely eliminate the risk.

You have to weigh the benefits of giving the medication with the potential downsides. The negative aspects of giving the medication is obviously the cost and potential side effects. This medication is known to be very safe but everyone has their own feelings about this whether they are based in fact or not. Some people don’t like their pets receiving any chemicals or drugs if they can avoid it. The best thing to do is ask your veterinarian about the side effects and judge for yourself whether you are comfortable with them. You can also call the manufacturer of the product and have them send you studies and information about the risks of the product.

I’ve found that my clients have very different feelings about the risks, benefits and costs of preventing heartworm. It’s important to educate yourself and hopefully, your veterinarian gives you an unbiased evaluation of your unique situation so you can make the decision yourself. Many people feel that their veterinarians simply have a blanket recommendation for testing and preventing heartworm disease and that they don’t evaluate everyone’s needs individually. Keep in mind that they also want to control the disease across their community rather than in just one pet.

Please watch our videos on heartworm for more information about the “General Info About Heartworm Disease in Dogs & Cats”, “Testing for Heartworm Disease and When It’s Necessary” and “Heartworm Disease Prevention in Dogs: When and Why to Use Medication” of the disease.

I hope this helps!

Dr. Greenway