The difference between OTC flea products and veterinary exclusive products


As long as I have been a veterinarian, I am amazed how flea products have advanced through the years. There are products that combine flea, intestinal parasites, and heartworm prevention in one. Oral flea products  are available that last as long as three months to protect against fleas. You have a collar that can provide up to 8 months of prevention against ticks and fleas (Seresto flea collar). Despite the increased availability of these products I am surprised to still see clients continue to use over-the-counter flea products. I still see clients who persist to choose products such as flea shampoos, flea collars, and OTC (over the counter) topical products for their flea prevention. So the question I will attempt to answer is there a difference between these products and the products you can get at your veterinarian a.k.a. veterinary exclusive?

Disclaimer about OTC flea products

I am writing this with the understanding that some products that were veterinary exclusive are now becoming readily available in retail stores. Some examples include the products Frontline and K9 Advantix. So when I refer to OTC products in this article, I am not referring to these former veterinary exclusive products.

The Flea life cycle

To understand how OTC and veterinary exclusive items differ, one must understand how the flea life cycle works. For flea control, most pet owners pet focus on what they can see which are the live fleas. What owners don’t realize is that killing the live adult fleas is only a small part of the battle. In fact, there are three other stages that need to be addressed to achieve complete flea control. One stage difficult to see is the egg stage, yet it is the most important to be controlled. Reason being it is the most numerous in the environment. An adult female typically  lays about 40 eggs a day. So if you do the math, if your pet has 5 female fleas, they have the potential to lay a total of 200 eggs per day. The next stage includes the larvae. These larvae are similar to maggots visually. These larvae eventually turn into pupae, the final stage of flea life cycle before an adult flea emerges. Flea pupae are resistant to all flea products.

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The Flea life cycle vs OTC products

Okay now let us look at how the life cycle factors in how OTC flea products differ from veterinary exclusive products. Let’s look at the most popular flea products which are flea shampoos and collars. These products either claim to kill or repel fleas. Despite the popularity of these products, most don’t have any effect on flea eggs which make up about %50 of the flea population! Most pet owners don’t put a flea collar or give a flea bath until they see a moderate amount of fleas. When the fleas first appear on the pet and the pet gets treated, it is likely that they have already laid hundreds of eggs. These eggs will fall off the pet and end up in the environment waiting to be hatch.

Flea collars

Let’s talk about flea collars. Pets with a flea collar typically don’t have fleas around their neck. When I part the hair around the tail and the hind limbs and I often note fleas concentrated there. The further away the collar is from the fleas, the less effective it is against them. The drug in the collar has minimal to no effect on fleas who reside on or near the tail.

Flea Shampoos

Now let’s discuss the ever so popular flea shampoo. Most flea shampoos are effective in killing adult fleas. However there are two problems with this product. One is that shampoos have little or no effect on the other stages of the flea life cycle. The other is that they don’t have a long residual effect. After a flea bath, your pet may be protected for a few days then the fleas will return. Therefore you may have to bathe your dog every week to provide complete protection.

Topical flea products

So what about the OTC topical flea drops? Many of these products use older pesticides for flea and tick control. Some of these older pesticides include organophosphates, carbamates, and pyrethrins. Many of these products are effective at killing flea and sometimes their eggs. Where these products may differ from veterinary exclusive topicals is percentage of kill rate. Percentage of kill rate refers to what percentage of fleas are killed during the application process. Most topical flea products claim they will kill fleas for a total of 30 days. This does not mean they will kill %100 percent of fleas during that time period. Many of these OTC products may only kill about %60-%70 2-3 weeks after their applications. This will still leave fleas to lay eggs even though fewer are present. The other problem is compared to veterinary exclusive topicals, these products are more likely to cause sensitivity reactions. Products that contain that contain pyrethrins as active ingredients are notorious to cause neurological problems in cats because of owners accidentally placing the product on them instead of dogs.

My final perspective

OTC flea products, may seem effective if you are dealing with a mild case of fleas, but be mindful that just because you don’t see fleas doesn’t mean that they are not there. I would recommend using a flea comb to determine if the OTC product is working and you may be surprised at the results. If you are dealing with a moderate or severe infection then the likelihood that an OTC product will work is less likely. Even if you are using a veterinary exclusive product, you have to remember that battling fleas is typically a 3 part process. One part involves treating the pet themselves, next is treating the environment, then finally any other pets in the household need to be on a preventative for flea control to be successful. One final note is if you use a topical flea product, you have to be careful with what you bathe your dog with. Some shampoos can make the topical product less effective over time. If you insist that your pet needs frequent baths, then you should strongly consider one of oral flea and tick products.



12 thoughts on “The difference between OTC flea products and veterinary exclusive products

  1. I have never had success with OTC flea products. I used Trifexis until this year on my dogs. It worked fine on my short haired dogs, but my husky still got some fleas. I use the original blue Dawn to bathe neonates and adult cats/dogs with fleas. The husky at times would get a dose of Capstar for fleas not killed by the Trifexis. Last Fall, I switched to using Bravecto for fleas and back to Heartgard for heartworms. I love the Bravecto! Neither the husky or my short haired dogs have had problems with fleas and I love the 3-month dosing. Also my dogs always readily chew the Heartgard and Bravecto. They all hated the Trifexis! I had to crush it and mix with cat food to get them to eat it.

  2. Interesting article concept, but irresponsible in that you completely neglected to mention how dangerous all of these chemicals are to the animal being treated, nor offered non-chemical alternatives. From our own experience with a serious adverse reaction to advantix that has haunted our dog for his life, to tons of corroborating information on-line, these chemical products are often very very harmful to animals. Essentially they are pesticides being added to the animal’s bloodstream and circulating through internal organs.

    It only makes sense that the strong manufacturers warnings about not touching the (at least topical) products, is a huge red flag that the stuff is dangerous. Yet vets, for the sake of the almighty dollar and people that ignorantly listen to them, force this stuff on innocent animals because the chemicals are more convenient than more naturalistic and admittedly less immediately effective alternatives, that in the long run, will save the animal’s health.

    • Well Ken with your comment it seems that you have completely neglected quite a few things as well. The first thing you seemed to have neglected is the purpose of the article. The purpose of the article was to ONLY compare OTC flea products with veterinary exclusive products. It was not to talk about all the available flea products that are available on the market. In fact there are no specific products that I was promoting as this was purely an informational article. The goal of the article was to talk about these categories of flea products in general. So it seems silly that it is expected of me to offer non-chemical alternatives when most of these don’t fall into any of those two categories. This is analogous to criticizing somebody for reviewing two types of cars that may have poor gas mileage, then accusing them for not offering more fuel efficient car options.
      Another factor you seem to have neglected with your comment is that a fair amount of people purchase flea products without input from the “big bad” veterinarians as you have seemed to refer to us as. Just a quick history lesson, until about 20 years ago, the OTC products were the only ones available to treat fleas in pets. So people have developed a habit to now first reach for these over the counter products with all the “dangerous” chemicals first before seeing us. They come to us only after they discover that these products are ineffective.
      Another issue you have failed to consider is the lack of credentials or knowledge that you have to comment about why all veterinarians feel the need to prescribe certain flea and tick preventatives. The fact that you can state with confidence that we only “force this stuff on innocent animals” for the sake of the “almighty dollar” indicates that you have limited knowledge of veterinary medicine. You lack the understanding that we deal with flea allergy dermatitis and tick borne diseases in pets. Both of which can cause significant discomfort for pets and sometimes require long expensive treatments. Sometimes death can even occur for the pets that succumb to tick borne diseases. In these cases choosing a natural product would be a poor option. Trust me I did not go to school for eight years and incur a significant school debt so I can push “deadly” flea products for the “almighty dollar”. I did it due to my compassion for animals. If I wanted a career to achieve the almighty dollar, veterinary medicine wouldn’t be my first choice.
      While it is unfortunate that your dog experienced an adverse reaction to a flea product, what is more unfortunate is that you chose to extrapolate your negative experience to all flea products, pet owners who choose to use flea products by calling them ignorant, and veterinarians who prescribe these meds by questioning their intent. Another factor you seem to have neglected is that all animals can have an allergic reaction to something. Does that make what they react to “dangerous”? No not at all. I even have seen a dog have an adverse reaction to a so called “natural” flea products. If I follow your logic then I would consider all flea product natural or chemical “dangerous” Just like if a child had an allergic reaction to nuts that doesn’t necessarily make all nuts dangerous and that all nut farmers are selling dangerous products for the all “mighty dollar”.
      The fact that you mention “on-line” information to assert these claims that all flea products are extremely dangerous shows that you neglect scientific facts. Of course you will find some people who will report reactions to every product out there. But in context they represent the expected minority. I think I would prefer to use peer reviewed research studies showing the improved safety of many of these newer products vs a bunch of online anecdotes that may or may not be true. To further corroborate this information, I also prefer to use my own personal extensive clinical experience where I have prescribed flea products to hundreds of pets without any adverse effects.
      If you wish to use just all natural products on your pets because of your negative experience with one flea product I won’t judge you or others for those choices. You need to do what you are comfortable with regarding your pets. Where you deserve judgment is when you decide to generalize all veterinarians and pet owners that don’t share your personal view in a poor light because of your dissenting view.

      • All I know is that it’s 5:40am and I haven’t slept a wink. My poor chihuahua mix I rescued has a bloody neck and is obviously in discomfort due to the Seresto flea collar he’s been wearing. His hair started falling out like crazy and I have had to change sheets daily. This collar was recommended by our vet. She meant well I am sure but when I expressed my concern over any flea collar and it poisoning my dog she assured me this was safe. 😾👎🏻 Obviously not. I googled to see if anyone else had seen hair loss and sores and lesions and lo and behold the internet is full of that and deaths related to this SERESTO flea collar. It should come with warnings. This is a sad day. Think of the suffering of these animals. They can’t tell you. Good lord!!!!! And now I will be charged for visit I am sure. Which is ridiculous 👎🏻 And then have to demand money back from petsmart. And complain to the big bad giant BAYER 🤦🏻‍♀️😖😤I am totally disgusted

  3. I commend you for not removing my comment from your blog, however your defensiveness, verbosity, and twisting of some of my statements, must indicate I’ve struck a nerve.

    A few key points:

    Regarding not promoting “specific products”, I didn’t say that you did such a thing, but be honest, the purpose of your blog is to promote patients coming to you for services and products, which will include veterinary exclusive flea/tick treatments. Specific brands are not the issue since you’re trying to position yourself as a credible source of information so that people will pay you for the class of drugs described in your article.

    Your veterinary degree does not confer more credentials upon you than me to opine why vets push these products. In fact, I have likely experienced their methods as a customer, more than you have. From my experience, the experience of many people we’ve come to know, and even admissions from two veterinary office managers, my experience is valid and likely very common.

    Lastly, in a world of pharmaceutical industry tainted veterinary school curriculums, peer reviewed studies are not always what they seem. As you know, they are often funded by drug companies looking for sympathetic sources to rubber stamp their findings. And your assumption that I’m quoting on-line anecdotes is misguided as well. If you doubt there are highly credible sources to back up my assertions, name the vet exclusive products that you think are safe and let people find their own answers.

    • Ken your response has me shaking my head. I think it was your full intent was to strike a nerve. The fact that you generalize all veterinarians over a bad experience with a flea preventative is quite troubling. Also this statement “people that ignorantly listen to them (veterinarians)” is quite unsettling. Who else are they suppose to listen to regarding their pet’s health? Self proclaimed pet experts who claim to know it all because they are masters with Google?
      First of all I don’t know how you can say that my blog is to promote patients coming to me for my services. Not anywhere on my blog do I list my clinic name or clinic contact information. The blog was just created to provide information from a veterinarian’s perspective. So your first point that you made regarding me trying to “position yourself as a credible source of information so that people will pay you for the class of drugs described in your article” is quite invalid. Even if you look at the product reviews I have written, you will clearly see that many of these products can be purchased on Amazon. In fact most of my clients don’t even know I have this blog.
      Also I am surprised that you would even state that talking to two veterinary office managers would validate your assertions. Given the fact that many veterinary office managers have little to no clinical experience or clinical education when it comes to veterinary medicine.
      It is equally as surprising that you would say your experience as a customer trumps my veterinary degree of why we promote these products. I know I promote these products because they are effective and help keep flea and tick related medical conditions to a minimum. Also a veterinary office manager is far from qualified to declare why veterinarians do what they do.
      To your last point I would like you name the veterinary school you know with certainty is pharmaceutical industry tainted. I see people make these statements yet can’t name any component of any veterinary school curriculum to prove their point. As far as peer reviewed studies that are supposedly funded by pharmaceutical companies those are different from the safety studies that are required by the FDA before any drug is able to be released on the market. Those you and anyone else can find the results of those studies in the insert of the package of the product. As far as naming exclusive products that I think are safe. Wouldn’t you just accuse me of promoting a product? I think the term “safe” means something different to a health care provider in comparison to a pet owner. For me I consider a product “safe” if it either the side effects listed are minimal, majority of the pets I personally prescribe the product to experience no adverse effects, or percentage of patients experiencing side effects listed in the FDA studies are below 5%. This is quite a contrast to a pet owner who may consider any product that causes any problems in their pet as “unsafe” which is the category I feel you fall under.
      Also regarding your highly credible sources I am curious of why you consider them highly credible. Is it because it falls in line with what you believe?
      But either way as I mentioned in my previous response with any drug I prescribe I always corroborate any research results with my clinical experience first. So if my clinical is different from research results then I question the validity of the study

    • Why is there no otc flea treatment that is effective??? Literally the only thing that beats them back is liberally poisoning my house and spending hundreds a year on poisoning my animal.
      Can you explain why it so expensive?? With the millions of animals having to be treated every year, why does the cost just climb every year.

      I’m not fond of taking an animal to the vet and being dinged $300 every year.

  4. I entered this blog because I love a less is more mentality. However I see people using the OTC products complaining about fleas. I use vet perscribed products and have no fleas. Of course I would love to use a cheaper alternative but I have found they just don’t work.

  5. I’ll have to make a few note’s on paper , with question’s – as I meet with my vet – to their best aproach to protect my pet , effectively – combating fleas & ticks etc. etc. !!!

  6. I have used the Seresto collar on my 6-month old labradoodle and I love it. We take her off leash running in the timber 2-4 times a week and I’ve yet to find a tick. If you read the Seresto instructions you are supposed to keep an eye on your pets neck for adverse reactions. How long did you leave the collar on before looking at your dogs neck if it bloody?

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