In my last column, I covered the many options for flea and tick prevention. Heartworm disease is becoming more common in New England. We are not only seeing a lot of dogs coming from the southern US, where heartworms are endemic, but we also see many home-grown heartworm cases. Annual prevention is a fraction of the cost of treatment—and treatment is painful and can be dangerous in certain cases.
We touched on 3-in-1 preventatives last month that are a great option. These are newer medications that prevent heartworm disease, fleas and ticks. They also typically prevent intestinal parasites as well. The most common we use are Nexgard Plus, Simparica Trio and Credelio Quattro.
More traditional heartworm preventions include Heartgard and Interceptor. Heartgard comes in two versions: regular, which only prevents heartworm, and plus, which includes coverage for intestinal parasites.
Heartgard’s primary ingredient is ivermectin. The dose of ivermectin is incredibly small so even dogs with certain genetic conditions can safely be on Heartgard. If you’ve ever had a dog with an MDR1 gene mutation, you may have stayed away from Heartgard in the past. This isn’t necessary but there are other options now for medications that are not ivermectin-based. Interceptor’s main ingredient is milbemycin. Both ivermectin and milbemycin work great as heartworm preventatives.
There is a long-acting injectable heartworm prevention called ProHeart. There are 6-month and 12-month injection options. This is a moxidectin-based extended-release product given by a veterinarian as a subcutaneous injection. When ProHeart first came onto the market, there were a lot of side effects in pets given the injections, including death. They have since reformulated the product. Unfortunately, once the injection is given, it cannot be taken away. So, if your pet has a reaction, the best we can do is manage it but we cannot take the medication away.
No matter what form of prevention you use, protecting your dog from heartworm disease is a must.