The main ingredients that prevent heartworms in dogs are ivermectin, milbemycin oxime, and moxidectin, which are all types of macrocyclic lactones that kill immature heartworm larvae before they mature. These ingredients are found in various monthly chewables and topical treatments, often combined with other medications for broader parasite control against fleas, ticks, and intestinal worms.
Oral Monthly Heartworm Medications
The heartworm preventives you are probably most familiar with are the once monthly tablets or chewables. These products typically contain either ivermectin or milbemycin as the active ingredient.
Best Heartworm Preventatives for Dogs
What is ivermectin? Ivermectin is most used as a heartworm preventive in dogs and cats. It also used “off label” or “extra label” for treating a variety of internal and external parasites.
All dogs need parasite prevention to protect against heartworms and intestinal worms. Ivermectin (Heartgard, Stromectol) has long been considered a safe and effective parasite preventative for dogs.
Moxidectin-doxycycline (moxi-doxy) provides a viable alternative to no treatment at all, in cases where arsenical treatment is not possible. Based on current evidence, the most effective non-arsenical treatment regimen is doxycycline 10 mg/kg PO q 12 or 24 h for 28 days, combined with topical moxidectin at label dose.
Although there are fewer mosquitoes in the winter, there is still a risk that your pet could get heartworms if you stop giving heartworm prevention medication during this season. That's one reason veterinarians strongly recommend pets receive heartworm prevention medication year-round.
However, Heartgard Plus Chewables cannot prevent the development of the adult stage. Use with caution for collies and other herding dog breeds. These breeds have been known to have adverse reactions to ivermectin at elevated dose levels.
(CN) – A federal class action claims the makers of a popular heartworm medicine have ignored 7 years of warnings from the FDA and jeopardized the lives of thousands of dogs by continuing to misrepresent the drug as “100 percent effective.” The class claims Merial misrepresented its HeartGard Plus medication because ...
Anecdotal evidence suggests that herbs such as garlic, black walnut and wormwood, and the homeopathic heartworm nosode, may actually prevent as well as treat infection.
If you have a breeding dog, a pregnant dog, or a puppy between 6 and 8 weeks old, Heartgard Plus is the safest option. If you're hoping to find a broad-spectrum product that protects against fleas and ticks while it defends against internal parasites, Simparica Trio is the clear winner.
Not all dogs with heartworm disease develop caval syndrome. However, if left untreated, heartworm disease will progress and damage the dog's heart, lungs, liver, and kidneys, eventually causing death.
5 Signs Your Dog May Have Heartworm Disease
Certainly, drug-free strategies can help reduce the risk of heartworm transmission to a dog or cat. Because heartworms are spread by mosquitoes, keeping pets indoors overnight and avoiding walks at dusk or dawn when mosquitoes may be feeding can help prevent exposure to mosquitoes that could be carrying heartworms.
3. Made with safe and effective ingredients.
Ivermectin is widely used to prevent heartworm disease in dogs through products like Heartgard, which kills immature heartworms before they mature. The American Heartworm Society recommends adulticide therapy using melarsomine injections as the primary treatment for heartworm-positive dogs.
The short answer to “Can I get heartworm medicine without a vet?” is no. Preventative medication to kill immature heartworm larvae will require a prescription from a veterinarian for several reasons. The Federal Food and Drug Administration regulates all medications, including heartworm preventatives for pets.
The dog is a natural host for heartworms, which means that heartworms that live inside the dog mature into adults, mate and produce offspring. If untreated, their numbers can increase, and dogs have been known to harbor several hundred worms in their bodies.
Approximately 1 in 500 cats nationwide test positive for heartworms each year. Heartworm rates are higher in Texas, Mississippi, Alabama and Louisiana, where 1 in 200 cats tested positive (see Louisiana-specific news release).
Myth #7: My indoor pet does not need heartworm prevention
All pets should receive heartworm prevention, whether they venture outside, or not. Mosquitoes certainly find their way inside—according to the American Heartworm Society, 25% of cats diagnosed with heartworm disease are indoor-only pets.
Moxidectin injectable (ProHeart 6®, ProHeart 12®) is used in dogs to prevent heartworm disease and treat existing hookworm infections. It is convenient for pet owners because an injection provides protection for several months.
" Heartworm preventives do not kill adult heartworms. Giving a heartworm preventive to a dog infected with adult heartworms may be harmful or deadly. If microfilariae are in the dog's bloodstream, the preventive may cause the microfilariae to suddenly die, triggering a shock-like reaction and possibly death.
Many dogs treated for heartworm have close to a normal life expectancy, depending on how quickly the disease was found. Without treatment, heartworm disease will shorten a dog's natural life expectancy.