Moxidectin is systemic as is Ivermectin. But Moxidectin stays in your body for 2 - 4 weeks. I personally would never take it without taking small doses of Ivermectin first and building up. They kill much of the same things. But I took Moxidectin when I had filaria (thinking I had Ascaris) and all the die off, immediately, almost put me in the hospital. So I would only ever take it after having built up on Ivermectin. 6 mg, 12 mg and because I am larger (since being sick), then 18 mg. I consider Moxidectin to be dangerous because it doesn't clear your system quickly. If you take to much, it is stuck in your body. Ivermectin clears your system in a day.