Timing of Enoxaparin Initiation After Fracture
Low molecular weight heparin (enoxaparin) should be started 12-24 hours after fracture surgery once hemostasis is established, and continued for 28-35 days in hip fracture patients. 1, 2
General Recommendations for Timing
- For patients with hip fractures, enoxaparin should be initiated 12-24 hours after surgery once adequate hemostasis has been established 1
- For patients with traumatic injuries including fractures, enoxaparin can be safely started approximately 24 hours after hospital admission 3
- In multiple trauma patients, enoxaparin should be started within 36 hours of injury to effectively reduce venous thromboembolism risk 1
Duration of Prophylaxis
- Extended prophylaxis of 28-35 days (4 weeks) is strongly recommended for hip fracture patients due to their high risk of venous thromboembolism 2
- For hip fracture surgery, thromboprophylaxis should be continued for a minimum of 7-10 days, but extended prophylaxis significantly reduces VTE risk 2, 1
- Studies show that the risk of venous thromboembolism remains elevated for several weeks after hip fracture surgery, making extended prophylaxis necessary 2
Dosing Considerations
- Standard prophylactic dosing for enoxaparin is 40 mg subcutaneously once daily for most patients 4
- For high-risk patients, enoxaparin 30 mg twice daily has shown efficacy in preventing deep vein thrombosis after hip surgery 5
- Some studies have demonstrated safety with higher doses (60 mg daily in split doses) in hip fracture patients when started before surgery and continued postoperatively 6
Special Considerations
- If neuraxial anesthesia (epidural) was used, prophylactic doses of enoxaparin should not be administered within 10-12 hours before epidural catheter removal 4
- The first dose of prophylactic enoxaparin can be administered no earlier than 2 hours after epidural catheter removal 4
- For patients with traumatic brain injury and stable CT findings, enoxaparin can be safely administered 24 hours after injury 7
Safety Profile
- When enoxaparin is started 12-24 hours after surgery, the risk of major bleeding complications is approximately 4-5% 5
- Studies comparing enoxaparin with other anticoagulants show similar safety profiles when timing guidelines are followed 8
- Early administration of enoxaparin (within 24 hours) has been shown to be safe even in patients with intracranial hemorrhagic injuries when appropriate patient selection is used 3
Common Pitfalls to Avoid
- Discontinuing prophylaxis too early (before 10-14 days) significantly increases the risk of venous thromboembolism 2
- Failure to extend prophylaxis beyond the hospital stay is a common error, as the risk of VTE remains elevated for several weeks after hip fracture surgery 2
- Starting enoxaparin too early after surgery, especially in patients who received neuraxial anesthesia, increases the risk of spinal hematoma 4
Alternative Options
- For patients with severe renal impairment (creatinine clearance <30 mL/min), unfractionated heparin is preferred over enoxaparin 2
- Mechanical prophylaxis methods (intermittent pneumatic compression devices) should be used in combination with pharmacological thromboprophylaxis when possible 4
- Extended prophylaxis after initial enoxaparin treatment can be continued with oral anticoagulants or aspirin in selected patients 8