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Fipronil (Frontline Top Spot)
Veterinary & Aquatic Services Department, Drs. Foster & Smith
Flea - Tick - External Parasites
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Generic Name

Brand Name
Frontline, Frontline Top Spot, Frontline Plus

Type of Drug

Form and Storage
Spray and oil spot on.
Store at room temperature.

Indications for Use
Treatment and prevention of fleas, ticks, and chewing lice infestations in dogs and cats.
Aids in the control of sarcoptic mange in dogs.

General Information
EPA approved for use on dogs and cats. Fipronil works by affecting the parasite's nervous system causing paralysis and death. Fipronil spreads over the body with the body oils in about 24 hours after application killing 100% of the fleas or ticks within 24-48 hours. Fleas and ticks are generally killed before they bite decreasing the risk of flea allergy dermatitis and tick-borne disease transmission.

Fipronil collects in the oils of the skin and hair follicles and then is released over time (up to 1 month) from the hair follicles onto the skin and hair. Hair that is shed after treatment will help decrease larval stages of fleas as the medication is on the hair. Frontline stays on even with bathing, swimming, or exposure to sunlight. Area of application may appear wet/oily for 24 hours. Allow to dry before touching the area. Do not reapply for 30 days. Frontline has been used off label to treat mites including ear mites and demodex. It is not soluble in water and has very little effect on the environment and wildlife.

Usual Dose and Administration
Apply the Top Spot or Frontline Plus oil to the pet's skin not the hair coat. Do not rub in.

Dogs: Individual pipettes are available for dogs in weight categories up to 22 pounds, 23-44 pounds, 45-88 pounds, and 89-132 pounds; over 132 pounds use the appropriate combination of pipettes or pipette plus spray.

Cats: Individual pipettes are per cat.

Spray on cats or dogs: 1-2 pumps per pound of body weight using the 250 ml bottle or 3-6 pumps per pound using the 100 ml bottle. Pets with long or dense hair receive the higher doses. Ruffle the hair coat while spraying. Hair coat should be damp to wet. To apply to the face, spray onto a glove and then wipe the glove over the face avoiding the eyes and mouth.

Do not apply 1-2 days before or after bathing as the natural body oils that help the drug spread will be temporarily removed with bathing. Apply once a month for continual protection from ticks. If in an area with few fleas and no ticks, Frontline may be applied every 2-3 months for flea protection.

Side Effects
May see temporary redness or itching at application site. The pet may drool if he licks the product (spray) before it dries.

Do not use in animals hypersensitive (allergic) to it.

Not to be taken internally. Do not get in eyes or mouth. Apply product to skin of pet.

Do not use on debilitated or aged animals.

Frontline Plus and Frontline Top Spot can be used on breeding, pregnant and lactating bitches and queens.

Do not use the Top Spot on kittens or puppies less than 8 weeks of age. The spray is approved in the United States for use at 8 weeks of age in puppies and kittens. The spray is approved for use in other countries for use in puppies and kittens as young as 2 days of age.

Treat all pets in the household for fleas, and treat the environment, or the problem will continue.

Treat year-round for best results or start before warm weather begins each spring in the northern states.

Drug Interactions
Do not use in combination with other pesticides especially on the pet.

May see irritation at site of application. If persists beyond a few hours, bathe the animal and contact your veterinarian.



Fipronil is a topical insecticide. It kills adult fleas and larvae, ticks, and chewing lice. It comes in two forms, a liquid that is applied to the skin along the back of dogs and cats, or a spray. If ingested, may see drooling. If irritation at the application site lasts for more than several hours, contact your veterinarian. Some animals may become hypersensitive (allergic) to fipronil.

Keep this and all other medications out of the reach of children and pets.

If you think your pet has been poisoned...

Contact your veterinarian or one of the Animal Poison Hotlines (listed below) if you think your pet may have accidentally received or been given an overdose of the medication.

**ASPCA Animal Poison Control Center - 24-hour service available throughout North America.

1-888-4ANI-HELP (1-888-426-4435). $65.00 per case, billed to caller's credit card.

Follow-up calls can be made for no additional charge by dialing 888-299-2973.

There is no charge when the call involves a product covered by the Animal Product Safety Service.

**Pet Poison Helpline - 24-hour service available throughout North America for pet owners and veterinary professionals who require assistance with treating a potentially poisoned pet.

1-800-213-6680 ($59.00 per incident). Staffed 24-hours a day.

Updated 6/20/17

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