The U.S. Food and Drug Administration Center for Veterinary Medicine has received reports of adverse reactions in dogs receiving the drug Comfortis (spinosad) concurrently with high, extra-label doses of the drug ivermectin. The clinical signs of these adverse reactions are consistent with ivermectin toxicity.

Comfortis (spinosad), manufactured by Elanco Animal Health, a division of Eli Lilly & Co., is a monthly oral, chewable tablet used for the prevention and treatment of flea infestations on dogs.

Veterinarians who use high, extra-label doses of ivermectin to treat dogs with non-responsive demodectic mange and other conditions should be aware that some dogs have developed signs of ivermectin toxicity when ivermectin is used concurrently with Comfortis (spinosad).

CVM and Elanco Animal Health are advising veterinarians that dogs receiving extra-label doses of ivermectin should not receive concurrent treatment with Comfortis (spinosad).

For more information, see elms.xh1.lilly.com/10788_03_tech_Bulletin.pdf or visit www.fda.gov/cvm.

Issued by:
FDA, Center for Veterinary Medicine,
Communications Staff, HFV-12
7519 Standish Place, Rockville, MD 20855
Telephone: (240) 276-9300 FAX: (240) 276-9115