The EPA Calls this Pest Treatment Ingredient a “Possible” Carcinogen

This summer, U.S. veterinarians will begin prescribing a brand new spot-on flea and tick preventive from Novartis Animal Health.

The product for dogs is called Parastar and the cat product is EasySpot. The active ingredient in these products is fipronil, an adult flea insecticide.

Per Veterinary Practice News:

“The Novartis family of parasiticides is defined by best-in-class medicine, so Parastar and EasySpot fit perfectly,” says Jason Drake, DVM, director of professional services at Novartis.

“Together with the heartworm preventive medicine that veterinarians choose most for their own dogs and the only systemic flea product with an insect growth regulator, the proven power of fipronil found in Parastar and EasySpot is a natural addition to the family.”

Veterinary Practice News June 9, 2011

Article url ;

Below is a Vets  comment on the  above

These two products, Parastar and EasySpot, are the first spot-on products introduced by Novartis in the U.S. The company does make a spot-on product called Prac-tic, with the active ingredient pyriprole, but it isn’t sold in this country.

Other flea and tick products by Novartis include:

Capstar (nitenpyram) tablets for dogs and cats. This is a flea treatment, not a preventive. Kills adult fleas.

Program (lufenuron) tablets for dogs and tablets, suspension and 6-month injectable for cats. This is a flea preventive; the tablets and suspension are intended to be given monthly. Kills fleas before they reach the adult stage.

Sentinel (milbemycin oxime/lufenuron) tablets for dogs is a combination product for the prevention of fleas, heartworms, roundworms, hookworms and whipworms. Recommended dosage is monthly.

Apparently Novartis was leaving money on the table and felt the need to add a spot-on flea/tick preventive to their U.S. product portfolio.

Fipronil, the Active Ingredient in the New Novartis Spot-on Products
Fipronil is a relatively new broad spectrum insecticide that acts by disrupting the central nervous system of insects.

Fipronil is used in a wide variety of applications beyond flea products, including cockroach and ant baits, termite control, agricultural products, and products used on turf and golf courses.

According to

“Fipronil has a different mode of action than many common insecticides. It is ‘an extremely active molecule.’ In insects, it disrupts the nerves in the brain and spinal cord by interfering with the ability of these nerve cells to transmit nerve impulses. The result is uncontrolled activity leading to death of the insect.

Fipronil also disrupts nerves in animals other than insects, including humans, but it does not bind as tightly to these nerve cells as it does to insect nerve cells.”
Symptoms of fipronil toxicity in pets include:

Loss of coordination
Symptoms of exposure in humans can include eye irritation, headache, dizziness, nausea and weakness.

In laboratory animals, fipronil caused kidney damage, significant alterations in thyroid function, and aggressive behavior. The product Frontline, which contains fipronil, also altered the levels of sex hormones in those animals. The offspring of pregnant lab animals exposed to the insecticide were smaller than normal and took longer to sexually mature.

The U.S. EPA has classified fipronil as a possible human (Class C) carcinogen due to the development of both benign and malignant thyroid tumors in laboratory animals exposed to it.

Minute concentrations of fipronil can prove toxic to several animals including birds, lizards and fish.

Fipronil lasts for a minimum of 56 days on pets, and people can be exposed by petting an animal that has been treated with a spot-on product containing the insecticide.

When exposed to light, fipronil can break down into a molecule called fipronil-desulfinyl. Per the EPA, this breakdown product is approximately 10 times more toxic than the fipronil itself. It is also more easily absorbed through skin than fipronil.

EPA Warning about Spot-on Flea/Tick Products Remains in Effect

Two years ago, the EPA issued an advisory about ‘spot-on’ products applied to the neck or back of pets to prevent fleas and ticks. The advisory was the result of a dramatic increase in adverse reactions to these products – reactions ranging from mild skin irritation to seizures and even death.

Among the problems the EPA found with spot-on flea and tick products:

The majority of adverse reactions were in dogs under three years old and between 10 and 20 pounds. High risk breeds included the Chihuahua, Shih Tzu, Miniature Poodle, Pomeranian, Dachshund, Maltese, Yorkshire Terrier and Bichon Frise.

Adverse reactions in cats were often the result of the kitty being treated with a product designed for dogs or through exposure to a treated dog.

Cats treated with dog products had a very high rate of serious reactions, including fatalities.

Dosage ranges on many products were considered too wide, and product labeling in general was identified as a problem.
In my opinion, the risks of these products are simply too great to warrant their routine (monthly) use. I encourage my dog and cat owner clients to avoid regular application of these pesticides in favor of safer alternatives.

2 Replies to “The EPA Calls this Pest Treatment Ingredient a “Possible” Carcinogen”

  1. Novartis Parastar and EasySpot are actually made by Sergeant’s!

    Instead of requiring Sergeant’s and Novartis to submit new companion animal safety and efficacy studies for those products, the EPA allowed them to cite studies that were submitted years ago for Frontline.

    Thanks, EPA, for once again failing to protect us from pet pesticide products that have been inadequately tested.

  2. I will use non chem. products on my dog for now on. I hate the drug comps. The gov. only cares about their selves and not dogs and cats. I would love to see one of the drug companies use these drugs on their children. Or around them.

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