Protocols based on daily to weekly oral or subcutaneous injections of macrocyclic lactones including ivermectin, doramectin and moxidectin at high doses are reported to provide variable efficacy, but may also have potential for toxicity, especially in dogs carrying MDR-1 gene mutations (P-glycoprotein deficiency), especially including Collie breeds [18, 20, 22]. The gene discussed is ABCB1; the disease is hyperinsulinemic hypoglycemia, familial, 4.