Abstract 4142117: First Reported Case of Massive Gastrointestinal Bleeding Linked to Piperacillin-Tazobactam in a Patient on Rivaroxaban: A Comprehensive Case Review

Introduction: The management of patients with Venous thromboembolism (VTE) receiving anticoagulant therapy is complicated by potential interactions with other medications, including antibiotics. Piperacillin-tazobactam (PTZ) has been implicated in unexpected disturbances in the coagulation cascade, which can be critical in patients concurrently using anticoagulants like rivaroxaban. This report explores the complexities of prescribing broad-spectrum antibiotics to patients with pre-existing cardiac conditions and the necessity of careful consideration of drug-drug interactions. Case Report: A 52-year-old white male with a history of deep vein thrombosis on rivaroxaban, presented with severe left leg cellulitis and subsequent gastrointestinal bleeding shortly after the initiation of piperacillin-tazobactam. His presentation was complicated by a rapid deterioration in his condition following a syncopal episode, characterized by hematochezia and hematemesis, necessitating urgent medical interventions including the cessation of all anticoagulation therapy, esophagogastroduodenoscopy and broad-spectrum antibiotics. Discussion: This case highlights the clinical challenges and potential risks of coagulopathies induced by PTZ or the interaction of PTZ with rivaroxaban, stressing the importance of multidisciplinary vigilance. The mechanisms by which PTZ may influence the coagulation pathways in patients already at risk due to their cardiac profiles underscore a significant area of concern for clinicians.