FORMULATION: «chews» for oral administration


CHEMICAL CLASS of the active ingredient(s): NEONICOTINOID


PARASITES CONTROLLED* (spectrum of activity): Fleas


  • Dogs or cats, 4 to 22 lbs. 1.8 to 10 kg bw: 1 soft chew with 11.4 mg imidacloprid (equivalent to 6.33 to 1.14 mg/kg imidacloprid)
  • Dogs, 23 to 110 lbs.  10.4 to 50 kg bw: 1 soft chew with 37,5 mg imidacloprid (equivalent 3.61 to 0.75 mg/kg imidacloprid)

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


  • LD50 (acute oral) in rats: >5000 mg/kg (calculated, according to SDS)
  • Estimated Hazard Class according to the WHO: not applicable for veterinary medicines

Suspected poisoning? Read the article on imidacloprid safety in this site.

WARNING !!!: Never use on cats or small dogs tablets approved for large dogs. Learn more about tablets 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, low in: fleas, mainly the cat flea, Ctenocephalides felis

So far there are no reports on flea resistance to neonicotinoids (dinotefuran, imidacloprid, nitenpyram). However, fleas have developed resistance to several other insecticides (e.g. carbamates, organophosphates and synthetic pyrethroids) and are certainly capable of becoming resistant to imidacloprid, as well. Experience shows that prolonged and uninterrupted use of any insecticide on fleas (including imidacloprid) bears the risk of resistance development. Consider also that imidacloprid, is also the a.i. of numerous other flea spot-ons (e.g. the ADVANTAGE-range) and belongs to the same chemical class as other a.i. (dinotefuran, nitenpyram ) in other flea products.

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 tablets.

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**?

  • Imidacloprid: GENERIC (introduced in the 1990s by BAYER)

*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: USA
GENERIC BRANDS available? Not yet?.

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


ADVANTUS is an original brand from BAYER (now ELANCO) with imidacloprid for the fast killing of fleas on dogs. Whereas most other topical and oral products start killing fleas 8-24 hours after administration and need 1 to 3 days to kill most fleas on a pet, ADVANTUS starts killing fleas 1 hour after administration, and 4 hours later 96% of the fleas are killed. However, it has no residual effect, i.e. protection against re-infestations is not longer than 1-2 days, in contrast with about 4 weeks for most spot-ons and other tablets against fleas.

Imidacloprid is a broad-spectrum neonicotinoid insecticide introduced in the 1990s (by BAYER). It is a broad-spectrum insecticide but without efficacy against ticks or mites. After oral administration it shows a systemic mode of action, i.e. it gets into the blood of the pet and reaches the fleas during their blood meal. It is abundantly used in pets (mostly in spot-ons for topical administration), but very scarcely in livestock. Imidacloprid is massively used in agriculture and quite abundantly also against household pests. 

Interestingly, BAYER introduced imidacloprid  for flea control in the 1990s as a spot-on (ADVANTAGE) for topical administrattion, but introduced ADVENTUS for oral administraion only about 20 years later.

Systemic products (tablets for oral administration, injectables) have several general advantages over topical products (spot-on, insecticide-impregnated collars, shampoos, soaps, sprays, powders, etc):

  • They do not contaminate the pet's hair coat: avoiding contact with the pets after administration is not necessary for children or adults.
  • The active ingredient reaches the parasites through the blood, everywhere in the pet's body, whereas topical products may leave some body parts (e.g. the ears, between the legs, etc.) insufficiently protected.
  • Efficacy is independent from exposure to dirt, sun, shampooing, washings, rain, baths, dirt, etc., whereas topical products can be washed away, or broken down by sunlight, etc.

But they have also a few disadvantages:

  • The parasite has to bite and suck blood first before it is killed or sterilized.
  • Orally administered products (tablets, suspensions, pastes, etc.) may be vomited and treatment needs to be repeated.
  • Administration of tablets may be less convenient than administration of spot-ons.
  • The choice of products for oral or injectable administration is smaller than for topical administration.

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.