A nurse is receiving a client who is immediately postoperative following hip arthroplasty. Which of the following medications should the nurse plan to administer for DVT prophylaxis?

Choice A rationale Enoxaparin is a low molecular weight heparin used as a first line pharmacological intervention for deep vein thrombosis prophylaxis after hip arthroplasty. It works by accelerating the activity of antithrombin III, which inhibits thrombin and factor Xa. This prevents the formation of fibrin clots in the venous system. Following orthopedic surgery, patients are at high risk for venous thromboembolism due to venous stasis and tissue trauma. Subcutaneous administration provides predictable anticoagulation with a lower risk of bleeding complications. Choice B rationale Warfarin is an oral anticoagulant that inhibits vitamin K dependent clotting factors, including factors II, VII, IX, and X. While effective for long term anticoagulation, it has a slow onset of action, often taking several days to reach a therapeutic International Normalized Ratio of 2.0 to 3.0. In the immediate postoperative period, rapid acting prophylaxis is preferred. Warfarin also requires frequent blood monitoring and has many drug interactions, making it less ideal than enoxaparin for the initial phase of postoperative DVT prevention. Choice C rationale Aspirin is an antiplatelet agent that inhibits cyclooxygenase 1, thereby preventing the synthesis of thromboxane A2. While it reduces platelet aggregation, it is generally considered less potent than anticoagulants like enoxaparin for preventing venous clots in high risk surgical patients. Current clinical guidelines often prioritize anticoagulants over antiplatelet monotherapy for DVT prophylaxis following major orthopedic procedures like hip replacement. It may be used in specific low risk scenarios, but enoxaparin remains the standard for immediate postoperative care. Choice D rationale Ondansetron is a selective serotonin 5-HT3 receptor antagonist used specifically for the prevention and treatment of postoperative nausea and vomiting. It has no effect on the coagulation cascade or platelet function. Therefore, it provides no protection against the development of deep vein thrombosis or pulmonary embolism. While it is a common medication administered in the recovery room to improve patient comfort, it does not fulfill the requirement for pharmacological thromboprophylaxis after a hip arthroplasty procedure.