What you should know about Over-the-Counter flea products

Ten years ago, we were controlling fleas the old fashioned way: fogging and spraying the house, powdering, spraying and shampooing the pets. The pets hated it. It smelled funny. It was hard work and yet it hardly worked.

We look back and barely remember all that now.  Today we can give a Capstar pill and rid a pet of fleas within an hour. We can apply oils behind a pet’s neck and achieve 30 days of flea protection.  The spread of these new generation long-acting topical flea products has brought flea control to a new level of both convenience and effectiveness.  And there are many of these topical products to choose from; in fact, sometimes it seems like every year there is a new one.

Many people do not realize that these are not simply different brands of the same product. In reality, the topical prescription flea medications are totally different from the over-the-counter ones and completely different from each other. It is the over-the-counter products that are largely the same and it is important to know when it might be a good idea to buy them and when it would be a waste of money.

How It Started

Going back to the days before the new generation products, there was one product that stood out among the sprays, foams, powders, and shampoos.  It was the first product that could dissolve in a dog’s skin oils and thus spread in the oil film all over a dog’s skin surface. A single application lasted for about a month. This product was called Defend Exspot and is still available today. At that time, however, it seemed like a miracle.  Its ability to spread in skin oil by itself was termed “translocation” and was due to the chemical properties of its active ingredient: “permethrin.”

What is Permethrin?

For hundreds of years insects have been controlled by using extracts from pyrethrum flowers.  These natural insecticides, called “pyrethrins,” were highly effective and are still widely used today.  Still, one of the problems with them was that they were very short-acting and could not deliver sustained insect killing power. Scientists began modifying pyrethrins and developed many pyrethrin versions that could last for long time periods.  The pyrethrin derivatives are called “pyrethroids.”  They are easily identified on a product label by their “ethrin” suffix. Common examples include: resmethrin, allethrin, and, of course, permethrin.

The permethrin based topical products offered many advantages:

Ø      Relative low cost compared to prescription products
 

Ø      Excellent tick protection as well as flea control
 

Ø      Some mosquito repellant properties
 

Ø      Ability to be combined with other insecticides without toxicity fears
 

Ø      Availability at most pet supply outlets

But there were some problems as well:

Ø      The high concentrations of permethrin needed for the translocation effect are extremely toxic to cats. This created not only a marketing problem but a health issue for families with both dogs and cats.
 

Ø      Permethrin is not waterproof. Bathing or swimming will wash it off.
 

Ø      Permethrin has been in use for over 20 years and many flea populations are resistant to it. This manifests as the product seeming to last only 2-3 weeks instead of the full 4 weeks. In many homes, permethrin has virtually no flea-killing ability at all.

It was no wonder that the advent of Bayer’s Advantage and Merial’s Frontline all but captured the market with their introduction in 1996.  With a huge safety margin, a feline version, and a new insecticide, there was virtually no flea resistance.  Frontline and Advantage also had major pharmaceutical companies to promote them and even with over-the-counter flea products slashing their prices, they were rapidly eclipsed.

Advantage and Frontline were soon followed by Revolution and other products sold only through veterinarians.  Public demand was high and low cost sources were sought, opening up a black market supplying pet stores and online pet pharmacies. Manufacturers of the permethrin products saw an opening and began to mimic the packaging of the prescription products, suggesting but never actually claiming to be a generic version of the safer more effective veterinary products.

Should You Use a Permethrin Product on Your Dog?

The bottom line for this decision involves weighing the pros and cons already listed.

Ø      If you are planning to use an over-the-counter permethrin product for flea control, weigh the low price against the resistance level of the fleas in your home.  After some 20 years of permethrin use, these products are not reliable for flea control. If they work for you, terrific. If not, a better product is probably worth the extra money.

 

Ø      Be aware that some dogs may have adverse reactions to permethrins as well.
 

Ø      Absolutely do not use these products in cats or on a dog that regularly snuggles up to a cat! These products use far too high a concentration of permethrin for cats.
 

Ø      Permethrin products excel when it comes to tick control.  You may want to use a prescription product for fleas and combine it with a permethrin product for ticks. Permethrin products are compatible with all the prescription flea control products, topical and oral.

If you are not sure what to use or what is compatible with what, always ask your veterinarian.

 

Kleinbrook Animal Hospital

(281) 444-8387