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Saturday, August 22, 2009

Follow-Up On Fleas & Frontline

My post yesterday generated several comments already, and I thought they were worthy of more discussion, especially if people don't always read the comments section. I'll copy the comments here.

In New Zealand, these products are vet only lines and the manufacturers will not sell to pet shops etc.It is a concern if these are to be so freely available as we need them to be sued properly, and to ensure the battle against the other 95% of the life cycle is also being fought in the environment!

Historically most of these products have been only available through veterinarians here in the US also. However, there are unscrupulous vets who buy these products in bulk and then sell them to other retailers who provide them to the public. Several manufacturers have gone after vets like this, but it's hard to control. I know that you can buy Fontline, Advantage, and K9 Advantix in places like PetCo, and I've heard that this is going to be more common. I think that some of these manufacturers are trying to get them sold through venues other than vets to increase their sales.

I believe Frontline resistance is already a happening thing in America?

A lot of vets and clients talk about this, but I believe it is all speculation so far. I haven't seen any studies that document this. And I've found that about 99% of the time when a client tells me that one of these preventions isn't working, it's actually because the client is doing something inappropriately (see my older posts on flea control). Currently I believe that "Frontline resistance" is mostly client mistakes or noncompliance. All of the talk of resistance is one vet or layperson talking to another suspecting it as the reason for failure of control, with no scientific data to support the opinion. The ingredients in the Advantage products have been studied world-wide and no resistance found. The Vectra line is new enough that there hasn't been time for resistance to develop.

Frontline is the ONLY product I've ever had a problem with. I was using Adams before and that wasn't doing it, went to frontline from the vet and Dispatch had a BAD reaction (was almost in a coma), a bath and a couple days and he was back to normal but I will never put it on him again. Might have been the leftover Adams spray from previously and the frontline but we will never know.

Adams is actually a must stronger product than Frontline, and is more likely to cause toxicities than Frontline. I've never heard of a reaction this severe with Frontline, and would more suspect that there was something else that happened. However, it is possible that he was a one-in-a-million case and had a personal sensitivity to the Frontline ingredients.

Could you give a little more detail on your rationale for preferring Advantix/Vectra over Frontline for flea/tick prevention? (In my area fleas exist but are mostly an afterthought to tick prevention - Lyme is the #1 thing we are trying to prevent with our FTP). My veterinarian recommends Frontline because of concerns about permethrin toxicity, which I see is an ingredient in both your recommended products. He also recommends Interceptor as a heartworm preventative, eliminating the need for a topical product that affects mosquitoes.

Good question! I have always felt that if any person or doctor has an opinion about something, they should darn well be able to support this opinion. You may or may not agree with them, but they should have the information to back it up.

First, I don't believe that permethrin toxicity is a real concern for your average dog. Yes, cats are very sensitive to it and can have life-treatening reactions. But these products are only dangerous to the cat if it licks it off the dog in the first 12 hours while it is wet, or if you apply a dog product to the cat. I have used Advantix since it came out and now Vectra, and have never had a problem with my cats around my dogs. Permethrin toxicity can happen in dogs, but generally only in very sensitive individuals and usually only at higher dosages. I have seen cats with this toxicity, but personally never dogs (though I know it does happen). For a dog, I don't think that the safety is any worse with permethrin than with fipronil. I don't think any of these products have strong enough mosquito protection to allow you to not use proper heartworm prevention, and that's less of a concern to me. Interceptor is a good prevention, and I have no problems with it.

Most of my preferences are based off the research and personal comments of two veterinary parasitologists, Dr. Mike Dryden of Kansas State University and Dr. Byron Blagburn of Auburn University. Both are world-respected specialists in flea and tick biology and control. A few years ago I heard Dr. Dryden lecture, and he gave the opinion that he slightly preferred the control of Advantix over Frontline, and that his studies showed that the Advantix had a slightly quicker flea and tick kill after application, though both performed about equally by the time of the next dosage 30 days later. Last Fall I attended a conference and spoke to Dr. Blagburn who was being sponsored to lecture by Bayer. He said that he really liked both Advantix and Vectra, but preferred the insect growth regulator in Vectra. If someone was starting for the first time, he leaned towards Vectra, but if there were no problems on Advantix there was no reason to switch and it was still a great product. In a short version, the ingredients in Vectra will help control more of the flea's life cycle than other products currently on the market, thereby granting better environmental and population control. In addition to all of this, I have seen other studies that indicate a slight advantage to Advantage/Advantix over Frontline (though I know that Merial has data to show the opposite). It's also comforting to me to know that the Advantage line has been tested for resitance and data proves that none exists; even though I'm skeptical about true Frontline resistance, I like having the data on my side.

In the end, I don't believe that Frontline is a bad product, and definitely better than any non-veterinary topical flea and tick preventions. However, based on my personal experiences, data I've seen, and the conversations I've had with specialists, I prefer to use Advantage, K9 Advantix, or Vectra on my own pets, and recommend these to my clients.

Good questions, everyone!


  1. Despite Ameria's reputation for litigation, I hope the unintentional use of sued instead of used in my comment is not held against me!

    We have those unscrupulous vets here too... but a smaller population to name and shame. Our latest saga is members of our own Vet Association setting up a web site to sell drench etc to farmers online, including vet only products... which is supposedly considered as offering vet advice. NOT going down well with the profession!

    Interesting re Advantix... some vets here are leaning that way now too.

  2. Heh, I would actually like for some of these people to be sued. ;)

    There are bad apples in any profession. I've received letters from people trying to get me to purchase these flea products, and have always been against it so I've just thrown them away. There are some people who put their personal greed over their morals or the overall good of their profession.

  3. I found your page googling "frontline resistance". :) I realize that your post is a bit older, but I can assure you that at least here in Chile frontline has become a lot less effective.

    I have used the product for over a year now and at first was amazed at its efficiency. It worked so well, that I only had to apply it every two months.

    With the amount of street dogs here, a "flea free" dog is fiction. :) If the fleas don't bother the humans and the dog isn't scratching itself to death: mission accomplished.

    A few months ago I moved to a different city. I still was on my 1-2 months routine with frontline, when I noticed my dog scratching excessively and producing quite a lot of flea eggs and feces. So I gave her a bath, applied a new dose of frontline the next day and everything was fine.

    Two weeks later I again noticed an increased amount of flea left-overs and scratching. Being confident, that frontline is good for at least a month, I scientifically concluded (read: made an uneducated guess) that maybe my earlier negligence allowed quite a few adult fleas to already be in the environment and just gave her another bath. That solved the problem for roughly three days.

    My next guess was that all the bathing maybe was counterproductive to the workings of frontline, hence I bought and applied another dose. It took two days and everything was fine: No eggs, no feces, and no flea to be seen. This again lasted roughly two weeks. Rinse repeat, next dose.

    It has now been 9 days since the last dose and probably due to my heightened attention in this matter I again just noticed large amounts of flea eggs and feces on the dog.

    Now correct me if I am wrong: The way frontline works, it should be impossible for a flea to reproduce on the dog, hence there should not be any flea eggs on the dog if frontline was working, right?

    (Of course there is the odd chance of a flea feeding some place else, ending up on the dog, and leaving eggs before it dies. But I'd be surprised if that number was significant, because the only other flea food in this house is me, and I'd know. :)

    Also the fact that frontline does indeed remove all/most fleas before reproducing for roughly a week points towards an increased resistance against the product, because of course the amount of active substance on/in the pet declines over time. Correct?

    The fact that I used frontline with great success for a while reduces the probability of user error, even though I did ask myself if I could have applied it wrong in one way or another, and took great care with the following doses. Also the very first dose I ever applied was not exactly accurately executed and still back then the product worked perfectly.

    Considering that the problem started when I moved to a new area, especially one with a higher dog population and frontline usage, I can only conclude that at least some fleas here require a much higher concentration of frontline to be affected by it.

    I'm going to try and find some Advantix now. It's much rarer here, which hopefully makes it as effective as hard to find. :)

  4. I'm still not convinced that there is resistance to Frontline, as it's been looked into and none found. Check out my most recent post for a discussion on this and links to other posts on this blog.


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