Effects of recombinant human activated protein C (rhAPC) on endotoxin (LPS)–induced coagulation. Healthy male volunteers received rhAPC (24 μg/kg per hour for 8 hours; ▪) or placebo (○) intravenously starting 2 hours before LPS challenge (2 ng/kg). rhAPC slightly reduced thrombin formation and action during the first 3 hours of infusion (indicated by asterisk), but LPS-induced thrombin generation was not blunted: thrombin antithrombin complexes (TAT; top graph), prothrombin fragment (F_{1 + 2;} middle graph), or d-dimer (bottom graph). *P < .005 versus baseline in the rhAPC groups and for relative change between groups, P < .001 for Friedman ANOVA for both groups, and P = ns between groups; mean ± SEM.