Did you know that there are unflavored heartworm preventative chews available, as well as other forms of preventatives? I didn’t either, until recently.
Pixel, my sister’s dog, was just diagnosed with a gastrointestinal disease that was causing inflammation of her intestinal tract and malabsorption of food. Fortunately, this condition was quickly resolved by changing Pixel’s diet to a novel protein and eliminating any foods with beef, pork, or chicken and she is now thriving. Then it became time to administer her monthly chewable heartworm preventative. My sister hesitated: The chewable preventative medication that she ordinarily used to protect Pixel was flavored with chicken, which Pixel couldn’t have. Fortunately, there are alternatives, and Pixel’s veterinarian was happy to change Pixel’s prescription to one of these.
Heartworm disease is a serious and potentially fatal condition caused by Dirofilaria immitis, a parasitic roundworm that is transmitted to dogs through the bite of a mosquito. Unfortunately, canines are natural hosts for the parasite, and once it infects a dog’s body, the larvae mature into adults, mate and reproduce, with the adult forms of the heartworm residing in the heart, lungs, and associated blood vessels. Heartworm disease can cause lasting damage to a dog’s body and have a long term effect on health and quality of life. Heartworm disease has been diagnosed in all 50 states; risk levels for contracting the disease vary and are difficult to assess. Accordingly, prevention is usually necessary in most areas. Heartworm medications do not actually prevent the transmission of the heartworm, but rather they act to destroy the larval stages of the parasite, preventing the development of the larvae into adult heartworms.
Prevention of heartworm disease is usually achieved by the monthly oral administration of a flavored chew, which is highly effective when administered correctly. Most oral heartworm preventives, however, contain a protein-based component for flavoring, usually pork, soy, beef, or chicken, in their formulation. Because many dogs suffer from food allergies and sensitivities or are undergoing food elimination trials (and flavorings can interfere with and affect the success of the trial), heartworm prevention in these cases should be changed to a non-flavored oral formula or topically applied product.
The monthly heartworm preventive HEARTGARD® (ivermectin) is available in an unflavored tablet form and does not include any food ingredients that may trigger an allergic reaction. A topical (applied externally to the body) heartworm preventative, such as Advantage Multi, Revolution, or Selarid, is another option, especially as this form completely bypasses the gastrointestinal tract.
There is a third option: ProHeart 6 and ProHeart 12 take the form of sustained released injections of moxidectin (this ingredient is also available as a topical) and provide protection from heartworm infection for six months and twelve months respectively. Its use in the U.S., however, still draws controversy over concerns regarding adverse effects (ProHeart 6 was taken off the market in 2004 because of safety concerns, but it was reformulated and returned in 2008; ProHeart 12 was approved for the first time by the FDA for use in the U.S. in July 2019). In other countries, both products remain on the market and are in use.
As always, consult with your veterinarian about your dog’s prescription heartworm preventative.
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