NexGard®, Bravecto®, Simparica®, Credelio®

Your Many New Oral Treatment Options For Flea, Tick & Mange Control On Your Dog – Some Approved For Cats

NexGard®, Bravecto®, Simparica®, Credelio® And The Same Company’s Products That Contain Added Ingredients To Combat Heartworms And Internal Parasites

Ron Hines DVM PhD

Fleas On Your Pets

Other Flea & Tick Options

  Products that cured mange NexGard®  Bravecto®

These four products are among the newer entrants in our unending battle against fleas and ticks. Besides the products shown in the photo above, Zoetis now mixes the Simparica® ingredients with moxidectin to prevent heartworms and pyrantel to prevent intestinal worms and markets the combination as Simparica Trio® . Boehringer-Ingelheim mixes their flea/tick ingredient, afoxolaner, with milbemycin to do the same thing and markets that as NexgardSpectra® In addition to Zoetis’ claims for Trio®, Boehringer states that Spectra® is an effective treatment for whipworms and lungworms  as well.

All of these products also offer your veterinarian a new treatment option for both demodectic and sarcoptic mange in dogs. That is because all of these parasites (including ear mites) depend on a bug’s (arthropod) nervous system being quite different from the one you and I and our furry friends share. (read here)

If your dog has been diagnosed with sarcoptic or demodectic mange, these newer medications might be a better and safer option than the products we veterinarians have relied on until now. That is particularly true if your dog is sensitive to ivermectin and similar products (read here)  or reacts poorly to amitraz (Mitaban®) dips.

NexGard® (afoxolaner),  Bravecto® (fluralaner), Symparica® (sarolaner) and Credelio® (lotilaner) all contain similar related compounds called isoxazolines. These compounds are distant relatives of fipronil – the active ingredient in Frontline®. Of the four, NexGard® has been on the market the longest (since 2013). So owner reports and feedback on that medication is the largest.

There is a caution on the label of all of these products that they be used with special care (if at all) in pets with a history of seizures or “neurological abnormalities”. None have been tested as to their safety in pregnant or nursing dogs. I would also be cautious about using any of these products in dogs under 4 months of age. I know that studies have found these products to be safe in puppies as young as 8 weeks old (read here) , but those were very limited studies. If you give your puppy a topical flea control product and it causes a problem you can wash it off. It you gave it in pill form there is not much you can do.  Bravecto® has or had on their label that reports exist of their product occasionally cause itching and hair loss in cats. Unless there is a picture of a cat on the package label, do not apply any of these products to a cat. Never apply any of these products in greater amounts than suggested on the product insert (instructions) unless your veterinarian agrees that that is the proper thing to do.

There is intense competition between these manufacturers – each attempting to outdo the others in claims for their particular brand. So I would take whatever claim they make as to the length of time a single dose is effective in preventing fleas with a grain of salt. Ticks are always more resistant to insecticides than fleas. Essentially the active ingredients in all of them are the same in effectiveness. They only differ enough to provide patent exclusivity. However the way a tablet is manufactured and the proprietary (secret) ingredients that might be added could conceivably make one brand slightly more effective or more readily eaten by your dog than another. If you are dissatisfied with how long flea or tick protection lasts or your dog spits them out, try another brand. I know that there is a warning on the box that the tablets must not be sold individually – as one would need to do to allow your dog make its own brand choice decision. But I also know that that warning is routinely ignored in the area where I live. 

Might These Medications Have Side Effects?

The makers report that side effects are uncommon and generally mild and the FDA, in their review, accepted that. The tests on these medications’ ability to kill fleas and ticks and the occurrence of side effects were run on young laboratory beagles. So they may not be indicative of what might occur in the general dog population.  In pet owner trials, when side effects occurred, they included, vomiting, dry flaky skin, diarrhea and decreased appetite. A few dog owners reported tremors, ataxia (staggering) , and seizures in their pets shortly after consuming the medications. But most owners reported that no side effects occurred during the rather brief period that the studies lasted. In company studies, more serious side effects were confined to dogs receiving higher than their suggested dose.

Some topical flea/tick medications such as Imidacloprid/Advantage® and Frontline®/fipronil kill fleas on contact. These oral chew tablets do not. The fleas have to “drink” the chemicals as it circulates in your pet’s blood stream. So dogs with serious fleabite allergies (actually allergies to flea saliva) may not be rid of their fleas before itching and skin damage begins. Those dogs need to rely on separation from flea exposure or a topically-applied flea control product. Read about that here

Are These New Medications Any More Effective In Controlling Fleas And Ticks Than What I Was Using Before?

None of the manufacturer studies compare the effectiveness of their product to more traditional topical or oral flea and tick control products that have been on the market for a long time. The FDA does not require that. The patents on most of those older products have expired and the original manufacturers (Zoetis, Boehringer, Elanco, etc.) now face less expensive generic competition. That might lead one to conclude that their newer offerings are no more effective against fleas and ticks than their older ones. One might also wonder if a quest for patent protection from generic competition was a major driving force in their development. Running comparative effectiveness studies would not be that difficult or expensive. If the manufacturers thought their new products out performed the older ones, they would almost certainly have run those studies by now.

Do You Suggest I Use Them On My Dog?

If you got to this page because you are trying to control fleas and ticks on your dog and the products that you are using now are working well for you, I see no reason for you to change. Their main advantage over topical products is convenience.  (You might be advised to switch during your pet’s next checkup because bigbox stores like Walmart now compete with veterinarians by offering lower cost generic flea and tick control products. see here

But if you got here because of a mange problem in your dog, that’s another story. Sometimes, a sarcoptic mange problem can be very hard for your veterinarian to entirely rule out as a cause of itch and dermatitis. In those cases, incorporating a few months of one of these products – even if atopic allergies are the more likely cause – might be good insurance. Allergy tests are not particularly accurate. (read here)

There are other factors to consider. When they are effective, I personally prefer using products on my dog that remain on the skin and hair coat rather than permeate my pet’s entire body. Other pet owners feel more comfortable knowing that topical insecticides are not on the skin and hair of the dogs and cats that they snuggle up to and that product residues are not being spread around their household environment. These oral flavor chews might be a better option for them. Others have pets that resist or fear the odor of topical flea/tick control products. There are also a number of pets that develop skin irritation and hair loss at the points where topical flea/tick control drops are applied. Elderly pet owners and others with mobility issues might just appreciate this oral, less-of-a-hassle approach.

I would not give these products to pregnant dogs until we have more information on what effects they might have on the offspring. But I know there are veterinarians dispensing Simparica® to pregnant breeder dogs in an attempt to keep them from producing puppies with demodectic mange. That might be successful. However, dogs that produce litters that are prone to generalized demodectic mange (such as shar-peis) all have inherited defective immune systems. I would never encourage a dog breeder to do so. ( read here & here )

You can read some other articles describing the use of these product’s to eliminate mange  here,   here,   here & here.

How Can We Learn More?

You can send me an email telling readers your experiences using these products. I will post them here anonymously. I am particularly interested in the good (or not so good) things that happened when these products were used and that stop when the products were discontinued. I would also like to know if you found them more effective against fleas and ticks than the topically applied products or collars you were using before.

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