There is an incredible amount of alarmist “information” out on websites, blogs, and social media groups about the dangers of monthly products, but there are surprisingly few helpfully informative websites to provide reassurance to concerned pet owners. The mindset seems to be to make owners more afraid of the disease than the treatment. Don’t get me wrong, all pet owners should be respectfully afraid of heartworm infections – I certainly am. The thought of worms filling up my dog’s heart to the point that heart failure takes her life after weeks of debilitating coughing and sickness keeps me appropriately reminded to give her the monthly pill. The thought of $1500 worth of painful treatment for heartworm disease scares my pocketbook when I could have prevented infection simply by giving her a pill that costs about $9/month.
Forget scare tactics. Let’s focus on how safe our recommended products are and why it’s GOOD to use them. Here’s some simple reassuring, yet important, information about administering heartworm prevention:
1) Heartworm prevention is really a dewormer. It is not prevention the way we think of common monthly preventatives. We call flea and tick medications that last in the body 30 days “prevention” because we can watch them killing parasites every day, thereby preventing infestations. Those style preventions work because the chemical stays effective in the body and kills the flea or tick when the flea or tick comes in contact with the pet. Heartworm prevention doesn’t remain in the body all month; it basically purges the body of the parasite if it is present. On average, the chemical stays in the body for less than 2 days and does not build up over time. In the south, it’s a very reasonable assumption that a mosquito has bitten your pet in the last 30 days. We give the medication to deworm monthly because of this assumption and the dose of medication we give clears that parasite from their system on that day. Other areas of the country may not recommend heartworm medications all year, but because our winters are not cold enough for long enough to eliminate mosquitoes for longer than a couple of weeks, we recommend coverage all year.
2) Heartworm preventions also prevent common intestinal parasites that can be acquired simply from the environment. The intestinal parasites they prevent are those worms that can be transmitted to people, especially young children (roundworms, hookworms). It is our duty as veterinarians and parents to be aware of and prevent diseases that can be transmitted to your family. We take this job seriously and it is a major reason why we recommend that annual fecal parasite test in addition to monthly heartworm prevention.
3) Still worried about heartworm prevention? The amount of the chemical used in common monthly heartworm prescription medications may be able to be reduced if your pet is sensitive to the medications. We can calculate the lowest amount that should be given on a monthly basis based on your dog’s weight and we can often find a compounding pharmacy that can create that specific dose. It may cost a little more, but if it prevents upset stomach in your pet and other options have been tried, this is a very good route to explore.
4) Some preventatives are still effective when used every 45 days. This reduces the amount of pills per year you would need to give your pet, either for financial or medication concerns. We do not ever recommend waiting longer than 45 days between heartworm pills because the developmental stage of the heartworm may be too resilient by that time to be killed off by the dose of heartworm prevention. Not all heartworm products can be used in this manner, so it’s important to double-check with your veterinarian or the drug company about their product. There are also regions in the country where some heartworms have developed resistance to some products. In this case, you would not want to wait until the last possible effective day to administer heartworm preventions.
There are many options for types of heartworm preventions and we are happy to discuss your pet’s needs to get them the best and most effective preventions available. Herbal options are not reliable or proven enough for us to trust with your pet’s life. If you still decide not to use heartworm prevention monthly on your pet, we would recommend testing your pet every 6 months so that if the worst happens and they do contract heartworms, we can start managing the disease as soon as possible before irreversible damage is done.
Dr. Tamara Rattray