The Evolving Role of Clinical Pharmacists in Pre-, Peri-, and Post-Operative and Critical Care Settings: A Comprehensive Review

Surgery is increasingly recognized as a complex, longitudinal therapeutic process spanning preoperative preparation, anesthesia, intraoperative care, and postoperative recovery rather than an isolated operating room event. Because this continuum is highly medication-intensive and subject to challenges like polypharmacy, rapid drug administration, physiological instability, multiple transitions of care, and communication failures, the perioperative environment carries a high risk for preventable medication errors. This review explores the evolving role of the clinical pharmacist, transitioning from a passive dispenser to an active, multidisciplinary collaborator throughout the surgical pathway. In the preoperative phase, clinical pharmacists improve patient safety by constructing a best possible medication history, clarifying continuation or cessation plans for high-risk home therapies (such as anticoagulants and antidiabetics), and delivering patient education to reduce morning-of-surgery non-adherence. In the intraoperative phase, they support anesthesia providers through system-level and case-level interventions, including the standardization of medication trays and labeling, antimicrobial prophylaxis stewardship, and multimodal analgesic design. Postoperatively, pharmacists collaborate with anesthesiologists to optimize acute pain management, support opioid stewardship, manage thromboembolism prophylaxis, and coordinate comprehensive discharge reconciliation to prevent drug duplication or omission. Collaborative models-such as joint acute pain services and pre-anesthesia consultations-render medication reviews clinically actionable and significantly enhance therapy optimization. Although challenges like staffing constraints, training gaps, and inconsistent clinical integration persist, the future of perioperative pharmacy lies in proactive, technology-enabled care incorporating clinical decision support, barcode administration, and artificial intelligence to solidify clinical pharmacists as core contributors to surgical patient safety.