Brand: VECTRA ®

Company: CEVA

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):


PARASITES CONTROLLED* (spectrum of activity): Fleas

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



  • Dogs & puppies, small 2.5 to 10 lbs. 1.1 to 9 kg bw: 1 pipette with 1,3 mL (equivalent 260 - 31.8 mg/kg dinotefuran, 35.5 - 4.3 mg/kg mg/kg pyriproxyfen)
  • Dogs, medium 11 to 20 lbs. 9.5 to 25 kg bw: 1 pipette with 2.0 mL (equivalent to 46.3 - 17.6 mg/kg dinotefuran, 6.5 - 2.4 mg/kg pyriproxyfen)
  • Dogs, large 21 to 55 lbs. 25.5 to 43 kg bw:  1 pipette with 4.0 mL (equivalent to 34.5 - 20.5 mg/kg dinotefuran, 4.7 - 2.8 mg/kg pyriproxyfen)
  • Dogs, very large 56 to 100 lbs. >43 kg bw: 1 pipette with 6.0 mL (equivalent to <30.7 mg/kg dinotefuran, <4.2 mg/kg pyriproxyfen)
  • Cats & kittens, small <9 lbs. <4 kgbw: 1 pipette with 0.8 mL (equivalent >44 mg/kg dinotefuran, >6 mg/kg mg/kg pyriproxyfen)
  • Cats, >9 lbs. ≈ >4 kg bw: 1 pipette with 1.2 mL (equivalent to <66 mg/kg dinotefuran, <9 mg/kg pyriproxyfen)

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


  • LD50 (acute oral) in rats: >5000 mg/kg (according to MSDS)
  • LD50 (acute dermal) in rats: >5000 mg/kg (according to MSDS)
  • Estimated Toxicity Class according to the WHOU unlikely to present acute hazard (based on the LD50, learn more)

Suspected poisoning? Read the articles on dinotefuran safety and pyriproxyfen safety in this site.

WARNING !!!: Never use on cats pipettes approved only for dogs. Never use on small dogs pipettes approved for large dogs. 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, low in fleas, mainly the cat flea, Ctenocephalides felis.

So far there are no reports on flea resistance to dinotefuran. However, fleas have developed resistance to several other insecticides (e.g. carbamates, organophosphates and pyrethroids) and are certainly capable of becoming resistant to dinotefuran as well. Experience shows that prolonged and uninterrupted use of any insecticide on fleas (including dinotefuran) bears the risk of resistance development. Consider also that dinotefuran belongs to the same chemical class as imidacloprid (ADVANTAGE, ADVANTIX, ADVOCATE from BAYER) and nitenpyram (CAPSTAR from NOVARTIS) and shows cross-resistance with these compounds.

There are no reports on resistance of fleas to pyriproxyfen either.

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**?

  • Dinotefuran: ORIGINAL (introduced in the 2000s by MITSUI)
  • Pyriproxyfen: GENERIC (introduced in the 1980s by SUMITOMO)

*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 (maybe under another TM): USA.

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


VECTRA is CEVA's original once-a-month fleaspot-on for dogs and cats. Only dinotefuran is "original" (from MITSUI). Pyriproxyfen is a veteran generic pesticide.

Administered about every 4 weeks, VECTRA 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 against fleas.

Dinotefuran is a broad-spectrum neonicotinoid insecticide introduced in the 1990s (by MITSUI). It is used in agriculture and only rather scarcely in pets, but not at all in livestock.

Pyriproxyfen (Nylar) is a veteran insect development inhibitor introduced in the 1980s (by SUMITOMO) scarcely used in pets. Its only effect is to stop development of flea eggs and larvae. It has no protective effect whatsoever against fleas. The logic of combining it with dinotefuran is to ensure that if a few fleas survive the killing effect of dinotefuran (what usually happens) development of their offspring is inhibited, because the eggs of the surviving fleas will not complete development.

This combination of two active ingredients of different chemical classes makes also sense regarding resistance prevention, because it means attacking fleas through two different mechanisms of action, which is vastly assumed to help preventing or at least delaying resistance development.

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.