FORMULATION: «injectable suspension»


CHEMICAL CLASS of the active ingredient(s):  BENZOYLPHENYL UREA


PARASITES CONTROLLED* (spectrum of activity): Fleas


  • Cats, small 8.8 lbs. = 4.0 kg bw: 1 pre-filled syringe with 0.4 ml (equivalent to >10.0 mg/kg lufenuron)
  • Cats, large, 8.9 to 17.6 lbs. = 4.0 to 8.0 kg bw: 1 pre-filled syringe with 0.8 ml (equivalent to 20.0 to 10.0 mg/kg lufenuron)

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


  • LD50 (acute oral) in rats: >2000 mg/kg for the a.i. lufenuron
  • Estimated Hazard Class according to the WHO: not applicable for veterinary medicines

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

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 lufenuron, 25 years after its introduction for flea control. However, fleas have developed resistance to several other insecticides (e.g. carbamates, organophosphates and pyrethroids) and are certainly capable of becoming resistant to lufenuron as well. Experience shows that prolonged and uninterrupted use of any insecticide on fleas (including lufenuron) bears the risk of resistance development.

Alternatives to prevent resistance through product rotation:

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

These alternative products are mostly not available as injectables, and may be are not available for cats.

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**?

  • Lufenuron: GENERIC (introduced in the 1990s)

*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: Worldwide, including the USA, the EU, Canada, Australia, etc.
GENERIC BRANDS available? YES, a few, but so far not as an injectable.

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


PROGRAM was NOVARTIS first and original brand with lufenuron, which was the first once-a-month tablet for flea prevention in dogs introduced in the early 1990s. Later on the injectable suspension was introduced only for cats. It offers unprecedented and so far unique 6 months prevention against flea infestations.

Lufenuron is an insect development inhibitor introduced in the lates 1980s (by CIBA-GEIGY → NOVARTIS → ELANCO). It is moderately used in pets, but not in livestock. It is also used in agricultural pesticides. Lufenuron has a systemic mode of action, i.e. after oral administration it get's into the blood of the pet and reaches the fleas during their blood meal.

Administered once it prevents flea infestations during about 6 months by inhibiting the development of eggs and larvae, but only if all the dogs and cats in the same household are treated against fleas. However, since it does not kill adult fleas, it is not suitable for treating established flea infestations unless used in combination with a flea adulticide. Best results are obtained when administered preventatively starting before the onset of the flea season.

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 & heartworm control click here.

A personal message

I was very heavily involved in the discovery of lufenuron in the 1990s during my years in NOVARTIS AH. Click here if you want to know more about the discovery and development of lufenuron and PROGRAM.


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.