Description: Moxidectin is an anthelmintic drug which kills parasitic worms (helminths), and is used for the prevention and control of heartworm and intestinal worms. Moxidectin is a semisynthetic derivative of nemadectin which is produced by fermentation by Streptomyces cyano-griseus. This Streptomyces species was discovered in a soil sample from Australia in the late 1980s collected by an agronomist working for the American Cyanamid company.