Did you know there are unflavoured heartworm preventive chews, as well as other forms of preventive drugs? I also didn’t do it until recently.
My sister’s dog, Pixel, was just diagnosed with gastrointestinal disease, causing inflammation of her intestinal tract and malabsorption of food. Fortunately, this condition was quickly remedied by switching Pixel’s diet to a novel protein and eliminating any food that contained beef, pork, or chicken. She is fine now. Then it was time to give her monthly heartworm preventative. My sister hesitated: the chewable preventive drugs she usually used to protect Pixel were flavored with chicken that Pixel couldn’t have. Fortunately, there are alternatives, and Pixel’s vet was happy to change Pixel’s prescription to one of them.
Heartworm disease is a serious and potentially fatal disease caused by Dirofilaria immitis, a parasitic roundworm that is transmitted to dogs by a mosquito bite. Unfortunately, canines are natural hosts for the parasite. 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 diseases can cause lasting damage to a dog’s body and have a long-term effect on health and quality of life. Heartworm disease was diagnosed in all 50 states. The risk of contracting the disease varies and is difficult to assess. Accordingly, prevention is usually necessary in most areas. Heartworm drugs do not actually prevent heartworm transmission, but instead destroy the larval stages of the parasite and prevent the larvae from developing into adult heartworms.
Heartworm disease prevention is usually accomplished by the monthly oral administration of a flavored chew, which when administered correctly is highly effective. However, most oral heartworm preventives contain a protein-based flavoring component, 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 flavors can and may interfere with the success of the trial), heartworm prevention should be switched to an unflavored oral formula or topical product in these cases.
The monthly heartworm preventive HEARTGARD® (ivermectin) is available in an unflavoured tablet form and does not contain any food ingredients that could cause an allergic reaction. Topical (applied externally to the body) heartworm prevention such as Advantage Multi, Revolution or Selarid is another option, especially since this form completely bypasses the gastrointestinal tract.
There is a third option: ProHeart 6 and ProHeart 12 are sustained-release injections of moxidectin (this ingredient is also available as a topical product) and provide six months and twelve months of protection against heartworm infections, respectively. However, its use in the US remains controversial due to concerns about adverse effects (ProHeart 6 was withdrawn from the market in 2004 for safety reasons, but reformulated and returned in 2008; ProHeart 12 was first approved by the EU FDA for use in the USA in July 2019). In other countries, both products remain on the market and are used.
As always, ask your veterinarian about your dog’s prescription heartworm preventive.
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