Abstract
This report describes three patients who developed marked somnolence and fatigue during treatment with avacopan for antineutrophil cytoplasmic antibody (ANCA) vasculitis. Though fatigue is a common symptom in ANCA vasculitis, each of these patients reported noticeable worsening of fatigue after starting avacopan, with improvement shortly after stopping the medication. All of them had a good response to treatment of their underlying vasculitis, and none of them had other clear causes of worsening fatigue.