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Information for Veterinarians

One of the most popular tick and flea adulticides in the world brought to you by Novartis Animal Health US, Inc.

Fipronil, the active ingredient in Parastar® for Dogs, is the most successful adulticide in small veterinary medicine due to its broad spectrum of activity, excellent safety profile and its long residual performance. The efficacy and safety of the molecule has been well established since its development in the mid-1990s and is still widely used today in Frontline® Plus.* For more detailed information, view the fact sheet.

How does it work?

Fipronil interacts with gamma aminobutyric acid (GABA)-gated and glutamate-gated chloride channels in the nervous systems of target species. It blocks inhibitory nerve transmission in susceptible ectoparasites, leading to hyperexcitability and death.


Fipronil is an ectoparasiticide that is effective against insects and some members of the order Acarina (e.g., ticks and mites). The two ectoparasites most often targeted by pet formulations are ticks and fleas. Fipronil is also active against mites that cause sarcoptic mange and chewing lice.

Chemical and physical properties

Fipronil's high lipophilicity and low water solubility play an important role in its residual efficacy. Fipronil is much less soluble in water than the active ingredients in competitive products, so it is less likely to be washed off.


  • Kills ticks and fleas quickly.
  • Remains effective between applications.
  • Waterproof.

Product Uses

Fipronil can be used on dogs and puppies 8 weeks of age and older weighing 4 lbs or more (Parastar for Dogs), and on cats and kittens 8 weeks of age and older weighing 4 lbs or more (EasySpot® for Cats).

Pet owners should be reminded to

  • Know the exact weight of the pet and use the appropriate dose for that size animal.
  • Read and follow label directions on the product package.
  • Make sure to use the appropriate product for the pet. It is especially important to avoid using a dog product on a cat.
  • Check with a veterinarian before using a tick and flea product on a debilitated, aged or medicated pet.

Are you a pet owner?

Ask your veterinarian why Parastar for Dogs is right for your dog.

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Are you a veterinarian?

Contact your Novartis Animal Health US, Inc. sales representative for more information.

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Want to learn more?

Get detailed information about Parastar for Dogs, and learn how it helps protect dogs from ticks, fleas and chewing lice.

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Parastar for Dogs is registered and available in every state.