Simulations of colistin plasma concentration-time profiles in ICU-HD patients receiving a 4-hour HD session on day n and dosed with 1.5 MIU q12h of CMS. The CMS dose planned before the HD session was postponed to immediately after the session and was 3 MIU. Curves were simulated with different values of CMS and colistin HD clearances reported in the literature, i.e., 94.8, 90, and 94.8 ml/min for CMS and 56.7, 137, and 66.5 ml/min for colistin (solid grey line, solid black line, and dashed black line), respectively (5, 7, 8). PK parameter values—except HD clearances—were fixed to estimates of the present analysis.