Jarisch-Herxheimer reaction the release of endotoxin when large numbers of organisms are killed by antibiotics. occurs about 8 hours after the first injection mild fever,malaise and headache lasting a few hours. Rarely,a severe reaction can occur 。prednisoneJarisch-Herxheimer reaction • the release of endotoxin when large numbers of organisms are killed by antibiotics. • occurs about 8 hours after the first injection • mild fever, malaise and headache lasting a few hours. • Rarely, a severe reaction can occur • prednisone