Company: ELANCO

FORMULATION: «spot-on» solution for topical administration on the back of the animals (also called pipettes, squeeze-ons, drop-ons, etc.)


CHEMICAL CLASS of the active ingredient(s):  SPINOSYN


PARASITES CONTROLLED* (spectrum of activity): Fleas

* Can be slightly different in some countries: read the product label!

RECOMMENDED DOSE: Cats (8 weeks) ≥  2 lbs. 0.9 kg bw: 1 pipette with 0.57 mL (=225.7 mg spinetoram), equivalent to <250 mg/kg)


  • LD50 (acute oral) in rats: >5000 mg/kg (not im MSDS; calculated according to the WHO based on the LD50 of spinetoram.)
  • Estimated Hazard Class calculated according to the WHO: unlikely to present acute hazard (based on the LD50, learn more)

WARNING !!!: Never use on cats pipettes approved only for dogs and vice-versa. Learn more about spot-ons and their safety.

You may be interested in the following articles in this site dealing with the general safety of veterinary products:


Risk of resistance? YES, but rather low in:

  • fleas, mainly the cat flea, Ctenocephalides felis

So far there are no confirmed reports on flea resistance to spinetoram. However, fleas have developed resistance to several other insecticides (e.g. carbamates, organophosphates and pyrethroids) and are certainly capable of becoming resistant to spinetoram as well. Experience shows that prolonged and uninterrupted use of any insecticide on fleas (including spinetoram) bears the risk of resistance development.

Alternatives to prevent resistance through product rotation:

*F = effective against fleas; T = effective against ticks.

These alternative products may not be available in all countries, or may not be available as spot-ons.

Resistance of fleas to carbamates, organophosphates and pyrethroids is not uncommon in several countries, including the USA.

Learn more about resistance and how it develops.


Are the active ingredients of this product ORIGINAL* or GENERICS**?

  • Spinetoram: ORIGINAL (introduced in the late 2000s)

*Meaning that they are still patent protected and generics are not yet available
**Meaning that they have lost patent protection and may be acquired from manufacturers of generic active ingredients other than the holder of the original patent.

COUNTRIES where this product is marketed: mainly in the USA

Click here to learn more about GENERIC vs. ORIGINAL drugs.


ASSURITY is ELANCO's original once-a-month spot-on for cats with spinetoram, an analogue of spinosad, belonging to the chemical class of the spinosyns. Spinetoram is used in crop protection pesticides but not on dogs or livestock.

Administered about every 4 weeks controls established flea infestations and prevents flea populations to develop in the pets environment, but only if all the dogs and cats in the same household are treated.

Spinetoram is an insecticide introduced in the 2000s (by DOW AGROSCIENCES). It is scarcely used in pets and agriculture, but not al all in livestock so far.

Another once-a-month fleas product for cats (and dogs) from ELANCO is COMFORTIS, but for oral administration as tablets.

Topical products (mainly spot-ons and insecticide-impregnated collars) have some advantages over systemic products (mainly tablets for oral administration and injectables):

  • Most topical products kill or sterilize the parasites before they bite and suck blood on the pet, whereas systemic products kill or sterilize the parasites only after their blood meal.
  • Topical products cannot be vomited.
  • Spot-ons and collars are very convenient to administer.
  • There is a larger choice of topical products.

But topical products have also some disadvantages:

  • Topical products contaminate the pet's hair coat and it is advisable for children and also adults to avoid contact with the pet for several days after treatment.
  • Topical products may not control parasites in some parts of the pet's body (e.g. the ears, below the tail, between the legs, etc.), whereas systemic products reach the blood-sucking parasites through the blood wherever they are.
  • Efficacy of topical products may be reduced or shortened through exposure to dirt, sun, shampooing, washing, rain, baths, etc., whereas efficacy of systemic products is independent from these factors.

For an overview and a list of the most popular pet antiparasitics for flea, tick, lice and/or mite control click here.


This article IS NOT A PRODUCT LABEL. It offers complementary information that may be useful to veterinary professionals and users that are not familiar with veterinary antiparasitics. 

Information offered in this article has been extracted from publications issued by manufacturers, government agencies (e.g. EMEA, FDA, USDA, etc.) or in the scientific literature. No guarantee is given on its accuracy, integrity, sufficiency, actuality and opportunity, and any liability is denied. Read the site's DISCLAIMER.

In case of doubt contact the manufacturer or a veterinary professional.