Major Uses

Spinosad is a flea control product for use in dogs. It is given once a month, works quickly, and kills fleas for an entire month. The drug works by activating nicotinic acetylcholine receptors in the nervous system of fleas. This action overloads the flea's nervous system, causing seizures and then death.

Spinosad belongs to the spinosyn class of insecticides. It is not approved or recommended for use in cats.

Common Precautions

Side effects associated with proper use of spinosad may include vomiting, reduced appetite, and diarrhea. Redness of the skin, lethargy, excessive salivation, and hyperactivity have also been reported. These side effects generally improve with continued use.

Spinosad is not for use in dogs with a pork allergy, as the drug contains pork protein. The drug is also to be avoided in pregnant and nursing animals and should not be used in puppies under 14 weeks of age.

This medication is for flea control only. It does not kill any other internal or external parasites and should not be relied upon for protection against these other threats. The drug should be used cautiously in dogs with a history of seizures. Spinosad is safe for use with other flea control products and drugs designed to prevent heartworms. However, the drug can increase the risk of ivermectin side effects when ivermectin is administered at high doses.

Spinosad should not be used in animals with a known allergy or hypersensitivity to the drug. Any known or suspected overdose should be reported to a veterinarian right away.


Spinosad should be stored in its original packaging, out of the reach of children and animals, and at room temperature.


Spinosad is available as chewable tablets in strengths of 140 mg, 240 mg, 560 mg, 810 mg, and 1620 mg. Spinosad is dosed by body weight. Ideally, spinosad should be given on a full stomach. The first dose should be administered a full month prior to the beginning of flea season.

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 spinosad is missed, it should be administered as soon as possible. If it is almost time for the next dose, the missed dose should be skipped and the normal schedule resumed. Two doses of this medication should not be given at once.

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.