How long should Lovenox (enoxaparin) 40mg be held before surgery?

Holding Lovenox 40 mg Before Surgery

For prophylactic-dose enoxaparin 40 mg daily, hold the last dose approximately 24 hours before surgery. This timing balances the need to minimize bleeding risk while maintaining adequate anticoagulation clearance before the procedure.

Timing Based on Dose and Surgery Type

Prophylactic Dose (40 mg daily)

• Hold for 24 hours before surgery for standard procedures 1
• The American College of Chest Physicians specifically recommends administering the last preoperative dose of prophylactic LMWH approximately 24 hours before surgery rather than 12 hours before 1
• This 24-hour window allows adequate clearance of anticoagulant effect while minimizing thrombotic risk 1

Special Considerations for Neuraxial Anesthesia

• If epidural or spinal anesthesia is planned, hold enoxaparin for 24 hours BEFORE catheter insertion or manipulation 1, 2
• This extended hold time is critical to prevent spinal hematoma, a catastrophic complication 2
• Resume enoxaparin no earlier than 2 hours AFTER catheter removal 2

High-Bleeding-Risk Surgery

• For procedures with particularly high bleeding risk, consider holding enoxaparin for 24 hours and potentially delaying resumption until 48-72 hours postoperatively 1
• The risks of bleeding must be weighed against thrombotic risk when determining exact timing 1

Postoperative Resumption

Standard Timing

• Resume enoxaparin 12-24 hours after surgery once hemostasis is established 3
• For hip arthroplasty specifically, initiation 12 hours before or after surgery is recommended 3

High-Bleeding-Risk Procedures

• Delay resumption to 48-72 hours after high-bleeding-risk surgery 1
• Use mechanical prophylaxis (intermittent pneumatic compression) until pharmacologic prophylaxis can be safely resumed 1, 3

Important Caveats

Renal Impairment

• For patients with creatinine clearance <30 mL/min, the prophylactic dose should be reduced to 30 mg daily, but the 24-hour hold time remains appropriate 1, 4

Obesity

• For patients weighing >150 kg, consider that they may be on 40 mg twice daily dosing 1
• If on twice-daily dosing, still hold for 24 hours before surgery 1

Major Trauma Patients

• In patients with recent major trauma, withhold enoxaparin for 2-3 days and only resume after careful risk-benefit assessment 1, 4

Common Pitfalls to Avoid

• Do not hold for only 12 hours - this is insufficient clearance time for prophylactic LMWH before surgery 1
• Do not confuse prophylactic dosing with therapeutic dosing - therapeutic-dose LMWH requires the same 24-hour hold, but the clinical context differs 1
• Do not forget about neuraxial anesthesia - failure to hold for 24 hours before epidural/spinal procedures can result in devastating spinal hematoma 2
• Do not resume too early postoperatively - wait at least 2 hours after epidural catheter removal and ensure adequate hemostasis 2