Major Uses

Fipronil, methoprene, and amitraz is a combination antiparasitic and insect growth regulator. It is used to kill fleas and chewing lice, repel and kill ticks, and treat sarcoptic mange in dogs. Proper use of the product helps prevent complications with flea and tick infestations, including skin allergies, irritation, and infection with Lyme disease, Rocky Mountain spotted fever, canine ehrlichiosis, babesiosis, anaplasmosis, hetatozoonosis, tick paralysis, tapeworm disease, bartonellosis, and others.

Fipronil, methoprene, and amitraz works rapidly to kill ticks within 6 hours of application and is effective at killing or preventing the development of all flea stages. It remains effective even after bathing or swimming. The product is highly toxic to cats and should only be used on dogs.

Common Precautions

Side effects associated with use of fipronil, methoprene, and amitraz include temporary lethargy and pruritis. These side effects typically become less bothersome within a few days. If they persist, a veterinarian should be consulted.

Fipronil, methoprene, and amitraz is for external use on dogs and puppies 8 weeks or older and weighing at least 5 lbs. The product is not for use on dogs with heart problems or diabetes. Caution is necessary when using on debilitated, obese, medicated, or aged dogs.

The combination of fipronil, methoprene, and amitraz is for use on dogs only. It should not ever be used on cats, rabbits, or other animals. The product is harmful if swallowed and can cause moderate eye and skin irritation.

Fipronil, methoprene, and amitraz may interact with other drugs or supplements. It is important to disclose all current and recent medications and supplements to a veterinarian before beginning treatment with fipronil, methoprene, and amitraz. Because amitraz is a monoamine oxidase inhibitor, anyone taking an MAOI drug should be extremely careful when coming into contact with this product.

Fipronil, methoprene, and amitraz should not be used in animals with a known allergy or hypersensitivity to the drug. The product should not be used more than once per month. Any known or suspected overdose should be reported to a veterinarian right away.


Fipronil, methoprene, and amitraz should be stored at room temperature, in the original packaging, and away from children and animals. The product is combustible and should not be exposed to heat sources or open flame. Partly filled containers require special disposal.


Fipronil, methoprene, and amitraz is available in various sizes for dogs and puppies of different weights. Dosing of fipronil, methoprene, and amitraz is based on weight. Detailed dosing and application instructions can be found inside the product carton. The product is for application to the base of the dog's skull and between the dog's shoulder blades and should be applied no more than once monthly.

Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

If a dose of fipronil, methoprene, and amitraz is missed, it should be applied as soon as possible. Two doses of this drug should never be applied at once or within any 30 day period.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.