Pharmacy Spotlight: Comfortis®
Drs. Foster & Smith Educational Staff

Spotlight on Comfortis

  • Medication type: Prescription-only insecticide derived from the naturally occurring bacterium Saccarapolyspora spinosa

  • Active ingredient: Spinosad

  • Dosage form: Monthly chewable tablets Flea Cycle

  • Manufacturer: Elanco

  • Generic Form: None

  • Major use: To kill fleas on dogs and prevent flea infestations for one month.

  • How it works: Saccarapolyspora spinosa interferes with the insect's neurotransmitters, causing the insect's paralysis and death. This medication eliminates existing infestations and prevents further infestations for one month.


Dog's Name: Georgie
Mixed BreedBreed: Female Mixed Breed
Age: 2 years

Her story: After a job-related move to Texas from a colder, northern climate, Georgie's owners found themselves dealing with a major flea problem. Not only were there more wild, roaming small animals in their new rural neighborhood, the folks next door had several cats and dogs that loved to visit Georgie. This scenario created a flea heaven in her backyard.

But it was no heaven for Georgie. The blood-sucking parasites made her life miserable. She began to scratch incessantly, and the owners tried many different products. They gave their dog regular baths and spent much time brushing her with a flea comb. But the fleas kept winning out. On a visit to their vet, they learned about a new medication, Comfortis®, the first FDA-approved, chewable, beef-flavored tablet that is effective in killing fleas and preventing infestations on dogs for a full month. The vet explained that the fleas start dying within thirty minutes, and that the active ingredient, Spinosad, is actually environmentally friendly.

Outcome: Georgie's owners were desperate, so they were eager to try the new medication. Within a short time of chewing the first tablet, several fleas fell off their dog and expired! In no time at all, Georgie's demeanor was totally improved. She had regained her former state of comfortable canine existence, something every dog is entitled to! Because Georgie lives in an area where fleas are common year-round, treatment with Comfortis™ will continue throughout the year. At their veterinarian's suggestion, the owners implemented the very practical measures of spraying the backyard and limiting the dog's exposure to areas of known flea infestation.

The veterinarian cautioned them to watch or vomiting, decreased appetite, lethargy, redness of the skin, hyperactivity, and excessive salivation, but, to date, there have been no signs of adverse reactions other than, perhaps, a slight decrease in the dog’s appetite. All in all, Georgie is faring well, and her owners, likewise, are enjoying the benefits of Comfortis™!

For full details on this medication, download the free patient information sheet.