The foundation of critical care medicine is high-quality supportive and frequent assessments to support a patient through their illness—all while preventing hospital-acquired complications. Mnemonics that include a focus on preventative care highlight the importance of these interventions. Pharmacists have a role in ensuring patient safety, optimizing medication therapy, and implementing evidence-based to prevent complications in critically ill patients. Key areas of focus include venous thromboembolism prophylaxis, infection prevention, prevention of hypoglycemia, stress ulcer prophylaxis, and more. By integrating pharmacists into the interdisciplinary critical care team, hospitals can enhance patient outcomes, reduce adverse events, and improve overall quality of care in the critical care setting. This chapter will focus on the therapies utilized to prevent certain hospital-acquired complications.