Choosing Heartworm Prevention Products

Laurie Anne Walden, DVM

Photo by kevin turcios on Unsplash

The differences between heartworm prevention products can be confusing. Some products protect pets from other parasites in addition to heartworms. Your veterinarian can recommend products for your own pet according to risk factors like your pet’s lifestyle, environment, and geographic location.
 
Heartworm preventives should be given all year round. If your pet’s heartworm preventive doesn’t also cover for fleas and intestinal parasites like roundworms and hookworms, your pet should receive a second product or have regular parasite tests (your veterinarian can advise you about this).
 
Heartworm preventives labeled for dogs and cats are available in the United States only by prescription. Some products that target fleas, ticks, and intestinal parasites are prescription products; others can be sold without a prescription. If you find a flea/tick product or a dewormer for dogs or cats that can be bought without a prescription, it won’t protect your pet against heartworm infection (unless it’s being sold illegally or possibly from outside the United States).
 
These are the parasites most often covered by parasite preventives for dogs and cats:

• Heartworms: potentially deadly for dogs, cats, and ferrets
• Fleas and ticks: carry diseases that are dangerous to humans and animals
• Roundworms and hookworms: contagious to humans, so prevention is an important public health issue
• Whipworms: contagious to dogs
• Tapeworms: spread to dogs and cats by fleas or rodents

 
Heartworm Preventives
New products come on the market regularly. Products within the same brand line that have different ingredients (for different parasite coverage) tend to have nearly identical names, so check labels carefully.
 
The following is a summary of currently available heartworm preventives for dogs and cats, listed by route of administration and active ingredient. This list is from the American Heartworm Society website, which shows the product names and their parasite coverage in an easy-to-read chart.
 
For an updated list of heartworm preventives for dogs, cats, and ferrets, please see the American Heartworm Society website: https://www.heartwormsociety.org/preventives
 
Products for Dogs
Tablets or chews given by mouth once a month:

• Ivermectin: Heartgard, Iverhart, Tri-Heart. For dogs, products containing only ivermectin protect only against heartworms. Some of the products in these brand lines also contain ingredients for hookworm, roundworm, and tapeworm protection.
• Milbemycin: Interceptor, MilbeGuard, Sentinel, Trifexis. Milbemycin by itself covers for heartworms, hookworms, roundworms, and whipworms. Some of these products also include an ingredient that kills fleas.
• Moxidectin: Simparica Trio, Nexgard Plus. These 2 products contain moxidectin (heartworm protection) in addition to other ingredients for flea, tick, hookworm, and roundworm protection. Plain Simparica (not Trio) and plain Nexgard (not Plus) don’t contain moxidectin and are not heartworm preventives; they are flea and tick products.

 
Injectable product given every 6 or 12 months:

• Moxidectin: ProHeart 6 (every 6 months), ProHeart 12 (every 12 months). These products provide continuous heartworm protection without owners having to give their dogs a monthly dose. They don’t prevent hookworm or roundworm infection and they don’t kill fleas or ticks.

 
Topical products applied to the skin once a month:

• Moxidectin: Advantage Multi, Imoxi, Parasedge Multi, Midamox. These products contain moxidectin plus another ingredient and cover for heartworms, fleas, hookworms, roundworms, and whipworms. There are several Advantage products; Advantage Multi is currently the only one with heartworm protection.
• Selamectin: Revolution, Paradyne, Senergy, Selarid, Revolt. In dogs, selamectin protects against heartworms, fleas, and ticks.

 
Products for Cats
Tablets or chews given by mouth once a month:

• Ivermectin: Heartgard. Heartgard for cats is labeled for both heartworm and hookworm protection.
• Milbemycin: Interceptor, MilbeGuard. These products provide heartworm, hookworm, and roundworm protection.

 
Topical products applied to the skin once a month (except Bravecto Plus):

• Moxidectin: Advantage Multi, Imoxi, Parasedge Multi, Midamox, Bravecto Plus. These products give heartworm, flea, hookworm, roundworm, and (depending on the product) tick protection. Bravecto Plus is applied every 2 months.
• Eprinomectin: Centragard, Nexgard Combo. These products give heartworm, hookworm, roundworm, and tapeworm protection. Nexgard Combo also covers for fleas and ticks.
• Selamectin: Revolution, Paradyne, Senergy, Selarid, Revolt. In cats, selamectin protects against heartworms, fleas, hookworms, and roundworms; some of these products also have an ingredient that kills ticks.

 
Image source: https://unsplash.com/photos/rls2bfqYh8E

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