Elanco, a sub-division of Eli Lilly, has announced a new flea product for cats called Assurity. I’ve already covered Evolve11 by Sergeant’s and discussed whether “new” means “safer” for pets and their people, especially toddlers. Let’s take a look at Assurity.

To understand where Assurity came from, we have take a little look at history. First, spinosad (the first spinosyn product) is an ingredient in the dog flea product that comes in pill form called Comfortis. One of the boons of Comfortis is that it comes in pill form so it does not allow the active ingredient residues in your home or for toddlers to come into contact with it. GreenPaws, which a site run by the Natural Resources Defense Council (NRDC), lists some common ingredients and rates them on toxicology, especially harm to humans. They give Comfortis one out of three paws for toxicity, which is a pretty good rating compared to other products.

In 1982, a vacationing scientist took soil samples from an abandoned rum distillery on a Caribbean Island. He found a naturally occurring soil baterium called Saccharopolyspora spinosa.  Apparently it is quite rare and has not been found elsewhere. In 1988, it was fermented for use as a biological pest control product similar to an insecticide. Spinosad works by over-exciting the insect’s nervous system, but it must be ingested. That means fleas, ticks, mosquitoes or whatever pest it is targeting, needs to bite and take in the spinosad. The claim is that since it must be taken in orally by the insects that it poses little risk to humans. It also means that with Comfortis, your dog has spinosad in their blood stream for quite a while. Because it is “natural” it is approved for use on organic crops as a pesticide much like pyrethrin is.

It makes sense, then, that there may be issues with topical use of spinosad and humans, especially toddlers. A new approval has just been given to the lice treatment, Natroba. (By the way, apparently slathering the head with vaseline and putting saran wrap tightly over the skull also kills lice.)

It is especially important to avoid treating patients 6 months and younger with spinosad, since it contains benzyl alcohol, which may cause serious adverse reactions — including death — in those patients, the FDA cautioned in a statement.

Benzyl alcohol is a wicked ingredient despite also being considered “organic”. It is a solvent for inks, paints, lacquers and epoxy resins. You can even use it as a photo developer. It is also included in many flea and tick spot on products. It poses a hidden danger, as one owner learned when his dog was treated with Advantage and his dog ended up stuck to the bottom of his crate due to benzyl alcohol in the product. Bayer, another member of Big Pharma (and also a manufacturer of agricultural pesticides) makes Advantage. Bayer also discovered an marketed propoxur, now the focus of an NRDC petition to the EPA, to attempt to remove this harmful ingredient, a known neurotoxin and carcinogen, from flea & tick collars.

Assurity for Cats is a topical product and contains spinetoram, similar to spinosad, but partially synthetic. It’s the first companion animal flea treatment to include this ingredient and, for marketing reasons, will only be sold through a vet. It  contains very high amounts of benzyl alcohol. Here is the patent info.

Such optional ingredients can be, for instance: benzyl alcohol, from 30-65%, and more normally 45-60%, by weight

Benzyl alcohol is one of those chemicals that cats have a very difficult time eliminating and so it becomes toxic to them very rapidly.

… benzoates have caused many fatal toxicities in cats…

Despite having a meeting with the EPA regarding spinetoram, most of my questions went unanswered. There is simply little public information available for spinetoram used as a pet product. However, it was confirmed that companion animal safety studies were performed on cats and using the entire formulary (which is rare in EPA procedures – usually only separate active ingredients are tested). However, those studies do not seem to been released publically yet. James TerBush, of BiospotVictims.org, has put in a Freedom of Information Request for cat specific studies, including home environment studies with toxicity to toddlers. Thanks to James & dedicated people like him, there is more information available than ever before about these products.

Dow Chemical has received awards from Green Chemistry Award and the EPA for finding “safer alternatives” with spinosad and spinetoram, primarily for crop use, but using it on cats as a topical seems reckless for the cats and especially the people living with their companion animals.

“The speed with which we received our first registration is creating a lot of excitement in the marketplace over this new generation of pest control,” says Don Kelley, global product manager, insecticides, for Dow AgroSciences

Speed is usually not the best measure of safety. Safety studies take at least 2 years to complete for each use type. When a pesticide is given conditional registration, they often are given the okay to market untested or not thoroughly tested products before submitting such tests. The conditional portion is supposed to be “okay, you can do this, but within the next two years we need you to submit the studies and back up your word that this is safe”. Sadly, once a chemical is on the market, it becomes difficult to remove it. To my layman’s eyes, it looks like studies for spinosad were used for spinetoram since they are similar in chemical structure. I have found references to this with the World Health Organization, Health Canada and the EPA. Since I don’t work for the government it’s difficult to know for sure what this means to the pet owner.

The EPA has not given much information on spinetoram to the public yet, so without all the information it is difficult, if not impossible, to make an educated assessment of the product. New pesticides are supposed to be posted on Regulations.gov and be open for comment. The docket for spinetoram that I found does not seem to address use on animals and is dated. It only has 8 entries. However, the old “trade secret” trick might be why these studies are lacking in the docket.

Although listed in the index, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information whose disclosure is restricted by statute.

This patent, also filed by Eli Lilly, only seems to have been tested on dogs. However, Health Canada, the Canadian version of the EPA in the United States seems to have released more information. Still, it appears to have been tested on almost everything except cats.

What concerns me most about the release of the Health Canada information is (my emphasis added):

Several metabolites were isolated, identified and characterized from urine and feces of rats treated with radiolabelled spinetoram. Spinetoram was almost completely metabolized by glutathione conjugation of the XDE-175-J parent compound, as well as glutathione conjugation with N-demethylated, O-deethylated and hydroxylated forms of the XDE-175-J parent compound, in conjunction with glutathione conjugation of the XDE-175-L parent compound, as well as glutathione conjugation with N-demethylated and O-deethylated forms of the XDE-175-L parent compound.

This may seem like a bunch of scientific gobbly-gook, but in relation to cats and their ability to metabolize spinetoram, it is significant. Glutathione is in every cell of a mammal body and is considered to be the most powerful antioxidant known to humankind. When your body becomes diseased, run down, traumatized and as you age, your stores of glutathione also deplete, causing chronic illnesses. In cats, their stores of glutathione are rapidly decreased, which is one reason why cats have more difficulty than most mammals in eliminating most essential oils, many chemicals and pesticides. In fact, glutathione is given to cats suffering from acetaminophen (the ingredient in Tylenol) toxicity as a treatment to help eliminate the acetaminophen from the body. (My emphasis added)

… metabolized with glutathione to nontoxic mercapturic acid (which is eliminated). If the toxic metabolites accumulate as a result of insufficient glucuronide or sulfate metabolism or insufficient glutathione, they are converted to toxic macromolecules that directly cause cellular death. Cats lack glucuronyl transferase and inefficiently form glucuronic acid and sulfate conjugates, leaving more acetaminophen or phenacetin to be metabolized to toxic metabolites. The glutathione stores are rapidly depleted in cats, leaving a large amount of toxic metabolites. Methemoglobinernia occurs.

Due to the extreme sensitivity of the cat to many things easily metabolized by other mammals, toxicity information for any other species does not necessarily mean that the same product or chemical is safe for a cat. This was an issue that we discussed in our August 2010 meeting with directors at the EPA.

As with so many “new” products, both synthetic and “natural”, designed to fight fleas & ticks, I am more than a little cautious and wary of Assurity and it’s long term safety for cats. Also, since it is a spot-on product, households that have children under the age of 6 should be incredibly careful. Toddlers are most susceptible to chemicals that effect their nervous and endocrine system and are at the highest risk of exposure (other than your pet) for topical flea control products. They often crawl on the ground, put things in their mouth they aren’t supposed to, pet or cuddle a household pet and then put fingers into their mouths.

Please see my list of alternatives. I research diligently and often ask manufacturers for more information. If I get double speak (which happens often, especially with “natural” products) or no answer after several attempts to contact the manufacturers, I do not recommend the use. At the best, it shows the company does not understand their product enough to explain it and at worst it shows they are not willing to go on record with ingredient, health or toxicity information. Pesticides should only be used IF you have an outbreak and WHEN all other methods have failed.


California Department of Pesticide Registration: Public Report

Wikipedia Eli Lilly History

Assurity 4 Cats Website (please download the label info and read it carefully)

This is an interesting site as well, as they have keeping a watch on Bayer for 30 years.

Special Thanks go to James TerBush whose tireless researching and willingness to share his knowledge are phenomenal. If you haven’t do so yet, check out BioSpotVictims.org and look through the archives. It’s well worth it!

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