how long to wait after lovenox before switching to heparin
â¢ Before surgery, wait at least 24 hours after the last dose of LMW heparin is administered before a spinal/epidural catheter is placed. â¢ After surgery, when there is adequate surgical site hemostasis, for twice daily dosing, wait at least 24 hours after catheter removal before resuming therapeutic-dose LMW heparin.