The present disclosure relates to, inter alia, compositions containing an inhibitor of human complement and use of the compositions in methods for treating or preventing complement-associated disorders. In some embodiments, the inhibitor is chronically administered to patients. In some embodiments, the inhibitor is administered to a patient in an amount and with a frequency to maintain systemic complement inhibition and prevent breakthrough. In some embodiments, the compositions contain an antibody, or antigen-binding fragment thereof, that binds to a human complement component C5 protein or a fragment of the protein such as C5a or C5b.