Fipronil (Frontline®)

Overview

Fipronil is a phenylpyrazole antiparasitic agent primarily used to kill adult fleas andticks.

It works by interfering with the brain and spinal cord of insects, resulting in death.

Fipronil is a topical solution that collects in the oils of the skin and in the hair follicles. It is not absorbed into the body and does not circulate through the blood stream. Through the process of translocation, it is spread over the body in about 24 hours. 

The effects of fipronil lasts about 30 days and remains effective after bathing or swimming though shampooing should be avoided within 48 hours of application.

Fipronil is a prescription drug and can only be obtained from a veterinarian or by prescription from a veterinarian.

Brand Names and Other Names

This drug is registered for use in animals only.

Human formulations: None

Veterinary formulations: Frontline® Top Spot (Merial) and Frontline® Spray Treatment (Merial)

Other veterinary formulations: Fipronil is an ingredient in Frontline Plus® where it is dispensed in a product that contains 9.8% fipronil and 8.8% methoprene.

Uses of Fipronil

Fipronil is used in the control and treatment of adult flea and tick infestations in dogs and cats.For more information on flea infestations, please see Flea Infestation in Catsand/or Flea Infestation in Dogs.

Fipronil is used for treatment and control of chewing lice in dogs, puppies, kittens and cats

Fipronil aids in the control of sarcoptic mange infestations in dogs. 

It has also been used to treat Cheyletiellosis (Walking Dandruff Mite)in dogs and cats.

Precautions and Side Effects

While generally safe and effective when prescribed by a veterinarian, fipronil can cause side effects in some animals.

Fipronil should not be used in animals with known hypersensitivity or allergy to the drug.

"Frontline Top Spot" is not recommended for use in debilitated or geriatric animals. 

"Frontline Spray Treatment" is not recommended for use in pregnant, debilitated, geriatric or nursing animals. 

Fipronil is not recommended for use in kittens and puppies less than 8 weeks of age.

Fipronil may interact with other medications. Consult with your veterinarian to determine if other drugs your pet is receiving could interact with fipronil.

Fipronil is a topical agent and temporary irritation at the site of application is possible.

Spotted areas may appear wet or oily for up to 24 hours. 

Overdose is rare and no adverse effects have been reported even up to 5 times the dose.

How Fipronil is Supplied

Fipronil is available in a topical 9.7 percent solution. Each card contains 3 or 6 pipettes. 

Fipronil is also available in a 0.29 percent topical spray, in a 100 ml bottle or 250 ml bottle. Each trigger spray of the 100 ml bottle is 0.5 ml of spray. Each trigger spray of the 250 ml bottle is 1.5 ml.

Dosing Information

Medication should never be administered without first consulting your veterinarian. 

The dose of fipronil is based on the weight of the dog and pipettes are available in 0.67 ml (for dogs up to 22 pounds), 1.34 ml (for dogs 23 to 44 pounds), 2.68 ml (for dogs 45 to 88 pounds) and 4 ml (for dogs 89 to 132 pounds). One pipette is applied topically every 30 days.

For cats, pipettes are available in 0.5 ml and one pipette is applied once monthly. 

The topical spray is dosed for dogs and cats at 1.5 to 3 ml per pound of body weight. This correlates to 1 to 2 pumps per pound with the 250 ml bottle and 3 to 6 pumps per pound with the 100 ml bottle. Animals with long hair need the higher dose. As with the pipettes, the spray is applied once monthly.

The duration of administration depends on the condition being treated, response to the medication and the development of any adverse effects. Be certain to complete the prescription unless specifically directed by your veterinarian. Even if your pet feels better, the entire treatment plan should be completed to prevent relapse or prevent the development of resistance.