New Study Shows Only REVOLUTION® (selamectin) Greater Than 90 Percent Effective Against Fleas 30 Days After Treatment

Topical medication lasts longer compared to prescription oral preventives

FLORHAM PARK, N.J., June 19, 2013 – Only the topical medication REVOLUTION (selamectin) remained more than 90 percent effective against fleas at Day 30 following treatment as compared to two leading oral tablets, according to a new study published in the online journal Parasites and Vectors. The study was conducted at the Kansas State University College of Veterinary Medicine and sponsored by Zoetis Inc., formerly the animal health business unit of Pfizer Inc.

Results of the study showed that selamectin administered topically at the label dose demonstrated activity that was more than 90 percent effective against the Ctenocephalides felis in dogs within two days after treatment and lasted for up to 30 days after treatment. Oral medications spinosad/milbemycin oxime and spinosad administered at the label dose were more than 90 percent effective within one day after treatment, but only up to 23 days after treatment.

“Fleas are a major contributor to the production of allergic dermatitis in dogs,” said Michael W. Dryden, DVM, PhD, DACVM, Department of Diagnostic Medicine/Pathobiology at Kansas State University, Manhattan, Kan., and lead author of the study. “While initial speed of flea kill is important, the residual speed of kill of a product is critical to the success of a flea control product.”

“Through this research, we can demonstrate that while other compounds may reach peak efficacy more quickly, REVOLUTION maintained greater than 90 percent efficacy for a longer period than the other medications tested in the study,” said J. Michael McFarland, DVM, DABVP, and group director of Companion Animal Veterinary Operations for Zoetis.

Study Details and Results

Forty-eight dogs were selected for the study, and two batches of 24 were blocked and allocated randomly to treatment groups and flea count times. There were four treatment groups of 12 dogs each: negative control, topical selamectin, oral spinosad/milbemycin oxide and oral spinosad. Each dog was infested with 100 fleas (C. felis KS1 strain) on Days -2, 7, 14, 21 and 28. Within each treatment group, six dogs were flea counted at 24 hours and six at 48 hours after treatment or post-infection. On Day 0, dogs received a single treatment of the appropriate drug according to approved commercial label.

Efficacy of selamectin against an existing flea infestation was 60.4 percent and 91.4 percent at 24 and 48 hours after treatment, respectively, whereas spinosad/milbemycin oxime and spinosad were 100 percent at both time points. All products were more than 90 percent effective within 24 and 48 hours after subsequent infestations on Days 7, 14 and 21. Following the Day 28 flea infestation, selamectin was 93 percent and 95.7 percent effective at 24 and 48 hours, respectively. The efficacy of spinosad/milbemycin oxime following the Day 28 infestation was 84.7 percent and 87.5 percent at 24 and 48 hours, respectively, and spinosad alone was 72.9 percent and 76.3 percent at 24 and 48 hours, respectively.

Following initial treatment, the two oral products containing spinosad had a more rapid onset of flea kill than topical selamectin, which took up to 48 hours to control (>90%) the existing infestation. However, for subsequent challenges, selamectin had similar or better efficacy than spinosad at both 24 and 48 hours after infestation and persistent efficacy of >90% for 30 days after treatment, while the two spinosad products had persistent efficacy >90% for only 23 days after treatment.

The complete study is available at


REVOLUTION (selamectin) is recommended for use in dogs six weeks of age or older, and kills adult fleas and prevents flea eggs from hatching for one month. REVOLUTION is indicated for the prevention and control of flea infestations (Ctenocephalides felis), prevention of heartworm disease caused by Dirofilaria immitis and the treatment and control of ear mite (Otodectes cynotis) infestations. REVOLUTION also is indicated for the treatment and control of sarcoptic mange (Sarcoptes scabiei) and for the control of tick infestations due to Dermacentor variabilis. More information about REVOLUTION is available at Information about REVOLUTION for use in cats is available at

IMPORTANT SAFETY INFORMATION: Do not use on sick, weak, or underweight animals. Use only on dogs 6 weeks and older. Use only on cats 8 weeks and older. Prior to administration, dogs should be tested for heartworms. In cats, side effects may include digestive upset and temporary hair loss at application site with possible inflammation. In humans, REVOLUTION may be irritating to skin and eyes. Wash hands after use.

About Zoetis

Zoetis (zō-EH-tis) is the leading animal health company, dedicated to supporting customers and businesses focused on raising and caring for livestock and companion animals. Building on a 60-year history as the animal health business of Pfizer, Zoetis discovers, develops, manufactures and markets veterinary vaccines and medicines, complemented by diagnostic products and genetic tests and supported by a range of services. The company generated annual revenues of $4.3 billion in 2012. It has more than 9,300 employees worldwide and a local presence in approximately 70 countries, including 29 manufacturing facilities in 11 countries. Its products serve veterinarians, livestock producers and people who raise and care for livestock and companion animals in 120 countries. For more information, visit or

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