The study of pharmacology enables the principle method of intervention for critically ill patients. Because many variables exists that affect the efficacy and indications for drug intervention, a thorough knowledge of pharmacology is needed in the intensive care unit, just as it is needed in the operating room. Because pharmacology effects every system it may potentially be included in every type of question. In order to achieve a pharmacologic focus, much of this chapter emphasizes and infrequently seen but non-isoteric contact. Overall, chapter is designed to evaluate pharmacologic knowledge with highly clinical vignettes for the reader. Additionally, the reader will find an emphasis on practice pharmacologic elements of managing infectious diseases and complexities of sedation, which anesthesiologists will find reminiscent of the residency training with a critical care “twist”.