General Questions

What are Comfortis® (spinosad) tablets?

They’re beef-flavored, chewable tablets you give to your dog or cat to kill fleas and prevent flea infestations for one month. Comfortis chewable tablets are recommended for monthly use in cats 14 weeks of age or older and 2 pounds of body weight or greater, and in dogs 14 weeks of age or older and 3.3 pounds of body weight or greater.

What is Spinosad?

Spinosad is the active ingredient in Comfortis. It belongs to a class of antiparasitics known as spinosyns, which are derived from a naturally-occurring soil microbe. It works by attacking the nervous system of insects, causing the rapid death of adult fleas.

When should treatment with Comfortis begin?

Treatment can begin at any time of the year. Comfortis is most effective when given one month before fleas become active, with continued monthly dosing through the end of the flea season. In areas where fleas are common year-round, monthly treatment with Comfortis chewable tablets should continue through the entire year without interruption. To minimize the likelihood of flea re-infestation, simultaneously treat all animals in your household with an approved flea protection product. Consult your veterinarian for the flea treatment options most appropriate for your area. See also, what should I discuss with my veterinarian regarding Comfortis for my dog or cat?