Type: Term Pronunciation: mok-sē-dek′tin Definitions: 1. An injectable macrocylic lactone antiparasitic used for control of Dirofilaria immitis heartworm and Ancylostoma caninum hookworms in heartworm-negative dogs; effect lasts 6 months; a semisynthetic avermectin class derivative of nemadectin isolated from Streptomyces cyaneogriseus n...